Re: Means of semantic differential scales
On 27 Feb 2002 15:01:24 -0800, [EMAIL PROTECTED] (Dennis Roberts) wrote: At 01:39 PM 2/27/02 -0600, Jay Warner wrote: Not stressful 1__ 2__ 3__ 4__ 5__ 6__ 7__ Very stressful just out of curiosity ... how many consider the above to be an example of a bipolar scale? i don't now, if we had an item like: sad happy 1 . 7 THEN the mid point becomes much more problematic ... since being a 4 ... is neither a downer nor upper The bipolar adjectives in Mr. Warner's example might be a tad fuzzy IMHO. What is a clear antonym for stressful? Pacified? Carefree? I noted same in my original response to his query. Your item sad...happy appears more like what Osgood et al had in mind. GoodBad, Hot...Cold, for example, are clearcut bipolars. If one wants to force an opinion one way or another, then display an even numbered scale. If the investigator wants the neutral opinion then make the scale odd numbered. To me the semantic differential is only a Likert Scale without the glitter :-)) I think his supervisor more than likely, however, was concerned about computing means with ordinal data. Perhaps, arguments can be made for both ordinal and interval usage depending on the intent of the research. Some semantic differential instruments I have seen in the past have no printed numerical scale at all. The respondent places a check mark along a horizontally gradated continuum. The researcher then assigns an appropriate score. vis a vis the check mark. Usually bipolar adjective items are randomly assigned, i.e., good responses are not all on one side of the document. Supposedly, the respondent can't simply halo the concept being evaluated. = Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at http://jse.stat.ncsu.edu/ =
Statistical Resources Site
The University of Michigan Documents Center has a Web site with links to statistical resources that might prove invaluable to those interested in a wide variety of data sources. Check it out. http://www.lib.umich.edu/govdocs/stats.html = Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at http://jse.stat.ncsu.edu/ =
Re: Need Statistic's on second hand smoke
On Sat, 16 Feb 2002 14:00:02 -0500, R. C. Lehman [EMAIL PROTECTED] wrote: Can someone tell me were to get Statistic's on second hand smoke.This is very important that I find the Statistic's on second hand smoke. R. C. Lehman [EMAIL PROTECTED] Thanx for any help you can give. Start with this web site first: http://www.epa.gov/iaq/pubs/etsbro.html = Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at http://jse.stat.ncsu.edu/ =
Transaction Anomaly on 9/11????
I recently read about German-based Convar helping cos. in NYC uncover the facts surrounding the unusual surge (both in volume and amounts) in financial transactions during immediately preceding the WTC disaster. Convar is using a laser scanning technology to recover data from computer hard drives, main frames, etc. for credit card cos. , telecom institutions, and accountants. The huge no. and size of transactions looks highly suspicious. OTOH, the U.S. could have gone on an absolutely wild shopping binge that day. Thinking damaged computers would be unable to track the money trail, some speculators may have moved approximately $100,000,000. Obviously, advance notice of the disaster would give savvy traders a field day. The problem is--- if such a blip was indeed the result of advanced knowledge and an unconscionable form of insider trading or just an unprecedented blip devoid of terrorist influence. What forms of statistical analyses could be employed to satisfy those with suspicion that such unusual events simply happen? Or, what methodologies can be used to estimate the probability of a very unusual event on a very unusual day. Is the notion of a conspiracy plausible? What statistical treatments, if any, would be apropos? I have some ideas, but would like others' views. Poisson applications? Differences in means (given similar uneventful day trading)? Any ideas or thoughts? One hopes it was simply an unusually heavy day, but it sure produces a wariness that those in the know profited from the misery of others. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Evaluating students: A Statistical Perspective
On Sun, 02 Dec 2001 19:19:38 -0500, Rich Ulrich [EMAIL PROTECTED] wrote: With the curve, and low, low averages, you do notice that a single *good* performance can outweigh several poor ones. So that is good. It is good, but conversely having several high scores even with low, low averages and then receiving a single disastrously low score can be a bummer of the first order. I remember this happening to me a couple of times...no fun at all! = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: N.Y. Times: Statistics, a Tool for Life, Is Getting Short Shrift
On 29 Nov 2001 07:03:13 -0800, [EMAIL PROTECTED] (Robert J. MacG. Dawson) wrote: There is probably a reverse trend in the extreme tail; people probably overestimate the probability of getting (say) red fifty times in a row at Roulette simply because we don't have a good feel for really large and small numbers. I think you are right in that assumption. When I taught probability, I found students had difficulty sensing numerical enormity or its opposite in scientific notation or lots of zeros. Dealing with 16 zeros to the right of the decimal, for example, becomes a complete abstraction. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: N.Y. Times: Statistics, a Tool for Life, Is Getting Short Shrift
On Fri, 30 Nov 2001 10:14:36 -0500, Rich Ulrich [EMAIL PROTECTED] wrote: - whereas, by contrast, we scientists can right it out with scientific notation with its powers of ten, and have something concrete, not abstract, because it is additive in the exponents or am I just making another complete abstraction of it? I'm sure you meant write it out, right? :-))) My point is that for many beginning students, a given probability with 16 zeros from the decimal is abstruse even if couched in sci. notation. IMHO, sci. notation is a symbolic representation of the real probablilty and is a handy tool for computation tasks as you point out. I agree with the original post that we don't have a good feel for the really large and really small numbers. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Definitions of Likert scale, Likert item, etc.
Rensis Likert was instrumental in founding the Institute for Social Research at the University of Michigan in the mid 1940s. He was truly a pioneer statistician and psychologist. He retired from Michigan in 1970 and passed away in 1981. Variants of his 1 to 5 or 1 to 7 scale are still found on many questionnaires in spite of the question about scaling, equal distances, etc. His studies on leadership and and production still hold interest. On 6 Sep 2001 14:48:44 -0700, [EMAIL PROTECTED] (Dennis Roberts) wrote: we do have a semantics problem with terms like this ... scale ... and confuse sometimes the actual physical paper and pencil instrument with the underlying continuum on which we are trying to place people so, even in likert's work ... he refers to THE attitude scales ... and then lists the items on each ... thus, it is easy to see an equating made between the collection of items ... nicely printed ... BEING the scale ... but really, the scale is not that ... one has to think about the SCORE value range ... that is possible ... when this physical thing (nicely printed collection of items) is administered to Ss ... thus ... for 10 typically response worded likert items with SA to SD ... the range of scores on the scale might be 10 to 50 ... of which any particular S might get any one of those values somewhere along the continuum but of course, scale is even deeper than that since, what we really have is a psychophysical problem ... that is, what is the functional relationship that links the physical scale ... 10 to 50 ... to the (assumed to exist) underlying psychological continuum ... PHYSICAL SCALE 10 (NEGATIVE) 50 (POSITIVE) PSYCHOLOGICAL CONTINUUM MOST NEGATIVE MOST POSITIVE problems like ... do equal distances along the physical scale ... equate to the same and equal distances along the psychological continuum? is there a linear relationship between these two? curvilinear? so, i think what we really mean by scale is this construct ... ie, the psychological continuum ... and a scale value would be where a S is along it ... but, about the best we can do to assess this is to see where the S is along the physical scale ... ie, where from 10 to 50 ... and use this as our PROXY measure ... BUT IN any case ... i think it is helpful NOT to call the actual instrument ... the paper and pencil collection of items ... THE scale ... _ dennis roberts, educational psychology, penn state university 208 cedar, AC 8148632401, mailto:[EMAIL PROTECTED] http://roberts.ed.psu.edu/users/droberts/drober~1.htm = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ = = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: [Q] testing the (bio)statistics minor
On Thu, 19 Jul 2001 13:45:35 GMT, Jerry Dallal [EMAIL PROTECTED] wrote: Some graduate programs in the (social) sciences require their students to take a minor in statistics or biostatistics. One purpose of such a minor is to give students the ability to analyze some of their own data, but at what level of understanding? Are such students expected to be able to synthesize the material they've learned, that is, rearrange it and apply it in new and possibly novel ways, or it is it more that they have a solid knowledge of standard techniques used in standard ways? (As I type this the answer seems self-evident!) The reason for these musings is that I'm being asked for advice on putting together a qualifying examination section for this type of minor and am finding the task daunting. I can imagine doing it by giving students 'typical' datasets to analyze, but that would make my job too easy. The committee would like it to be done orally! My instincts say that students exposed to such courses will invariably come up short when asked, Why? That is, their knowledge of underlying theory is weak by design and is perhaps unavoidable given the goals and time constraints of a 3 course minor. My instinct is to say the task is impossible. That is, some skills can be tested by having students apply them to data, but the nature of the 3 course minor precludes being able to judge a student's ability orally. I would be grateful for others' opinions on the subject. Thanks! An oral qualifying examination would certainly test the students' abilities to perform under stress. How about giving them the data sets beforehand and enable them to prepare for any and all queries from the student's doctoral committee members and/or other designated questioners? Rather than having the questions come out of the blue, they would be able to assemble notes, ideas, and a construct for solving a research problem using the methods learned in the classes. If the 3 course requirement is indeed a valid minor, then why not accept the results of the student's successful completion of same? One must have some faith in the integrity of the faculty on this one in so far as any grading system (or oral exam for that matter) is concerned. Is the qualifying exam, in this instance, to gauge the adequacy of the 3 course requirement? I'm curious what the 3 courses are, e.g., 2 statistics courses and a research methodology class? 3 straight stat classes? Are these courses the same for all social science degree candidates? I could come up with questions for those with a statistics minor (based on 3 courses). Would these questions measure what it is they are supposed to measure? Probably not. Good luck. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Late Absentee Ballot Acceptance Rates in Florida
In an exhaustive investigation, the N.Y. Times has studied the acceptance pattern of absentee ballots which arrived in Florida following the November election. In an analysis of the 2,490 ballots from Americans living abroad that were counted as legal votes after The Times found 680 questionable votes. Although it is not known for whom the flawed ballots were cast, 4 out of 5 were accepted in counties carried by Mr. Bush, The Times found. The counties carried by Mr. Gore accepted 20% that had no evidence they were mailed on or before Election Day. Counties carried by Mr. Bush accepted 60% of the same kinds of ballots. Bush counties were 4 times as likely as Gore counties to count ballots lacking witness signatures and addresses. Since the envelopes containing the absentee ballots were separated from the ballots themselves, no information about the voter was available: The Times asked Gary King, a Harvard expert on voting patterns and statistical models, what would have happened had the flawed ballots been discarded. He concluded that there was no way to declare a winner with mathematical certainty under those circumstances. His best estimate, he said, was that Mr. Bush's margin would have been reduced to 245 votes. Dr. King estimated that there was only a slight chance that discarding the questionable ballots would have made Mr. Gore the winner. It just gets curiouser and curiouser. If interested, the complete article is online: http://www.nytimes.com/2001/07/15/national/15BALL.html = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: What does it mean?
On Mon, 09 Jul 2001 12:15:25 GMT, Jan Sjogren [EMAIL PROTECTED] wrote: Hi there! I wonder what these things means: SST SSM SSE SSR MSR MSE Thanks, Janne Are these statistical acronyms you want defined? SSt, for example, could be total sum of squares and SSe could be sum of squares error. SST could denote the Concorde aircraft type or a Russian TU 144. MSe could be the mean square error in ANOVA. Of course, MSe could be the degree of Master of Science in Engineering too. My suggestion would be to try Google and see what develops.Some of these acronyms fit several known word patterns. You might give us some reference to the things about which you are wondering---so others can give you a better assist than I have herein. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: What does it mean?
On 9 Jul 2001 07:20:05 -0700, [EMAIL PROTECTED] (Robert J. MacG. Dawson) wrote: J. Williams wrote: On Mon, 09 Jul 2001 12:15:25 GMT, Jan Sjogren [EMAIL PROTECTED] wrote: Hi there! I wonder what these things means: SST SSM SSE SSR MSR MSE Thanks, Janne Are these statistical acronyms you want defined? SSt, for example, could be total sum of squares and SSe could be sum of squares error. SST could denote the Concorde aircraft type or a Russian TU 144. Oh, come *on*. Somebody posts to a stats mailing list with a list of closely related stats acronyms and we start winding them up with the suggestion that SST might be an airplane? What other plausible model would explain that list of acronyms as a set? Jeeesh. I guess residing near the Kennedy Space Center and many associated aerospace companies blinded me a bit to the obvious. Mea Culpa. j.w. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: cigs figs
Mr. Ulrich complains my 91 year-old deceased mother's concept of her right to smoke is provocative to me.Wow! Either he has too much time on his hands or some really serious problems that can't be solved through a statistics newsgroup. How my dead mother's attitude toward smoking created such an emotional tirade is beyond me. The bizarre and convoluted allusion to Justices Scalia and Thomas seems to be another of Mr. Ulrich's hot buttons my mother inadvertently pushed from her grave. I suppose he thinks she was a part of the vast right wing conspiracy he seems to be railing about. What Mr. Ulrich doesn't know is she was not only a lifelong smoker, but a Democratic Party activist as well. As yet, Mr. Ulrich has not provided the case law attributed to the two Justices re: smoking rights vis a vis Natural Law. IMHO, his apparent need to spout Democratic Party ideology would be more appropriate for a political science grouping. Possibly, his political ranting plays well to the gallery in Pittsburgh. Are they lucky, or what? On Sun, 01 Jul 2001 19:08:44 -0400, Rich Ulrich [EMAIL PROTECTED] wrote: - in respect of the up-coming U.S. holiday - On Mon, 25 Jun 2001 11:49:47 GMT, mackeral@remove~this~first~yahoo.com (J. Williams) wrote: On Sun, 24 Jun 2001 16:37:48 -0400, Rich Ulrich [EMAIL PROTECTED] wrote: What rights are denied to smokers? JW Many smokers, including my late mother, feel being unable to smoke on a commerical aircraft, sit anywhere in a restaurant, etc. were violation of her rights. I don't agree as a non-smoker, but that was her viewpoint until the day she died. What's your point: She was a crabby old lady, whining (or whinging) about fancied 'rights'? You don't introduce anything that seems inalienable or self-evident (if I may introduce July-4th language). Nobody stopped her from smoking as long as she kept it away from other people-who-would-be-offended. Okay, we form governments to help assure each other of rights. Lately, the law sees fit to stop some assaults from happening, even though it did not always do that in the past. - the offender still has quite a bit of leeway; if you don't cause fatal diseases, you legally can offend quite a lot. We finally have laws about smoking. But she wants the law to stop at HER convenience? [ snip, various ] JW Talking about confused and/or politically driven, what do Scalia and Thomas have to do with smoking rights? Please cite the case law. I mention rights because that did seem to be a attitude you mentioned that was (as you see) provocative to me. I toss in S T, because I think that, to a large extent, they share your mother's preference for a casual, self-centered definition of rights. And they are Supreme Court justices. [ Well, they don't say, This is what *I* want these two translate the blame/ credit to Nature (euphemism for God).] So: I don't fault your mother *too* harshly, when Justices hardly do better. Even though a prolonged skew was needed, to end up with two like this. -- Rich Ulrich, [EMAIL PROTECTED] http://www.pitt.edu/~wpilib/index.html = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: cigs figs
On 17 Jun 2001 14:47:14 GMT, [EMAIL PROTECTED] (EugeneGall) wrote: On Slate, there is quite a good discussion of the meaning and probabilistic basis of the statement that 1 in 3 teen smokers will die of cancer. It is written by a math prof and it is one of the most effective lay discussions I've seen of the use of probabilities in describing health risks. http://slate.msn.com/math/01-06-14/math.asp Maybe, I just notice it more, but it seems to me as I move about that more and more young people are smoking. Could it be that even with all of the negatives, smoking is still popular and/or growing among teeny boppers and young adults? Recent jury awards to long-time smokers seem to intimate that even with printed warnings, etc., the tobacco companies are ultimately responsible for respiratory and circulatory ailments. Smokers it is assumed are addicts and consequently not responsible for their actions. A salient point in Mr. Ellenberg's treatise is the query that of a sample of 100,000 deaths of male smokers, would 60,000 still be alive had they eschewed coffin nails throughout their lifetimes? My mother was 91 years old when she died a year ago and chain smoked since her college days. She defended the tobacco companies for years saying, it didn't hurt me. She outlived most of her doctors. Upon quoting statistics and research on the subject, her view was that I, like other do gooders and non-smokers, wanted to deny smokers their rights. Obviously, there is a health connection. How strong that connection is, is what makes this a unique statistical conundrum. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: The False Placebo Effect
On 26 May 2001 03:43:06 GMT, Elliot Cramer [EMAIL PROTECTED] wrote: J. Williams mackeral@remove~this~first~yahoo.com wrote: : On 25 May 2001 19:39:50 GMT, Elliot Cramer [EMAIL PROTECTED] : wrote: : do you suppose a person receiving a placebo can actually : change his/her diastolic reading? sure; I raised mine 20 points yesterday just thinking about someone misusing statistics. cholesterol is another thing. just sitting for 3 minutes before testing will lower it Are you sure you're not thinking about your systolic reading? Hypertension is diagnosed when the systolic blood pressure is 140 mm Hg or higher or the diastolic blood pressure is 90 mm Hg or higher. Most blood pressure readings in the office are taken after the patient sits down and relaxes for 5-10 minutes and, if found unusual, are taken again after a second period of rest. Recently, both systolic and diastolic are used in conjunction to determine hypertension according to an NIH study in 1999. The former reading, however, is the more volatile one. Stress, activity, etc. are more noticeable in the systolic figure. I seriously doubt if someone misusing statistics could hike your diastolic reading by 20 mm Hg :-)) If so, get treatment---fast--before you stroke out. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: The False Placebo Effect
On 25 May 2001 19:39:50 GMT, Elliot Cramer [EMAIL PROTECTED] wrote: I am not impressed. I don't think much of people who compare placebo with no treatment; seems stupid to me. I would expect a placebo in any case in which the evaluation is a human judgement or one's expectation could reasonably be expected to affect a measured response. Thus I think you could easily get an effect in a blood pressure measurement but not cholesterol. The rationale for employing a placebo is that this particular patient treatment group is receiving something whereas the no treatment (control) group is not. In many instances there are indeed ethical concerns, e.g., not treating someone with severe hypertension for the sake of study sanctity. The idea, of course, is to determine if the patient actually improves or just thinks he/she is better. Regardless, do you suppose a person receiving a placebo can actually change his/her diastolic reading? If so, let's treat hypertensives with placebos! On an issue such as self-reported pain measures, for example, the Danish researchers are probably correct IMHO due to the subjective nature of the rating scale. Also, some people get better no matter if they are in the placebo or no-treatment groupings which muddies the waters even more. Let's say we set up this research project: We randomly select 3 groups of 100 patients suffering from hypertension. We analyze the variances of their initial readings to assure the groups are essentially equal from the get go. Next, for one month we give Group A an experimental Rx designed to reduce blood pressure readings; Group B gets a sugar pill; Group C receives no treatment. At the end of the month, we take final readings. My hunch is the placebo group would not differ significantly on the diastolic reading from the no-treatment group. Even though the placebo patients think they are being treated, I wager they can't fake a diastolic reading. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Help me an idiot
On 30 Apr 2001 12:18:55 -0700, [EMAIL PROTECTED] (Robert R Johnson) wrote: Several have written to this thread and I believe there has been some misleading information passed along and intermixed with correct information. Possibly, you missed it, but I posted the correct answer last Saturday night telling the kid wanting help with his homework that it was somewhere near 32 combinations after another poster had inadvertently given him the no. of permutations. The only reason I said somewhere was so I would not bring down the wrath of those on the newsgroup opposed to giving a straight answer to a homework assignment :-))) Your response was quite helpful and a good learning tool. On Sun, 29 Apr 2001 11:26:11 -0400 Zina Taran [EMAIL PROTECTED] writes: I believe, the thrust of the fries reply was the overcount in the 5*4*3*. response rather than an expression of culinary preferences. Multiplying 5*4*3... is the kind of multiplication used when determining the 'number of permutations'. I seem to remember the question asked for number of combinations. The first step to obtaining the answer is to be sure you understand what you are 'counting.' If PERMUTATIONS - If you consider a hamburger with lettuce and mayo to be different than a hamburger with mayo and lettuce, then you want to count the number of permutations. Permutations involve the concept of order [rather it be 'the order in which you listed the condiments when placing the order' or 'the order in which the condiments are placed on your burger'] as an integral part of the problem. As applied to this particular problem, there were 5 condiments - for the first condiment selected there are 5 choices, for the second condiment selected there would be 4 choices available, and so on. Then by multiplying, you find the number of possibilities. I seriously doubt that you are interested in counting the number of permutations. If COMBINATIONS - If what you want to know is how many different combinations of condiments can be ordered, with no regards to an order concept, then you are interested in counting the number of combinations. It is this concept that I would think answers the question asked. One way to approach this is to look at and determine the count for each case, then find the total. [This approach was suggested in an earlier e-mail.] Five (5) condiments to choose from - 1) find the number of ways you can select exactly zero (0) condiments - there is 1, 2) find the number of ways you can select exactly one (1) condiment - there are 5, 3) find the number of ways you can select exactly two (2) condiments - there are 10, 4) find the number of ways you can select exactly three (3) condiments - there are 10, 5) find the number of ways you can select exactly four (4) condiments - there are 5, 6) find the number of ways you can select exactly five (5) condiments - there are 1, I'll leave it to you to find each of them. Answer: 1+5+10+10+5+1 = 32 different possible combinations of condiments can be ordered. If you are not interested in all the cases individually, there is a shorter way. Think of each different condiment that you can order, say pickles - you have 2 choices - 'order it' or 'don't order it'. The same two (2) options are available for each of the other condiments - catsup, mayo, lettuce, etc. [even for the fries and onion rings, if you want them included as a condiment on your burger. :-} ] Now what you have is a special case of the basic Multiplication Rule. Two (2) choices for each condiment, 2*2*2* ... *2, using 'n' 2's, or 2**n. Thus, if you have 5 condiments to choose from, there are 2**5 = 32 different combinations of condiments can be ordered for your hamburger. I hope this helps. - Robert R. Barbara S. Johnson E-mail: [EMAIL PROTECTED] Post: 84 West Lake Rd., Branchport, NY 14418 = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ = = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Help me an idiot
On 29 Apr 2001 04:09:05 GMT, [EMAIL PROTECTED] (Eric Bohlman) wrote: I wanted that with *fries* and *ketchup*! *Not* ketchup and fries! We hear you, but fries were not included in the original problem...only the 5 condiments. But you're right, fries would be good with that! Order me one. You could make this a really nice little problem by adding in fries to the no. of possible combinations. Put onion rings in the option list too. With or without a shake would be a nice touch too. But, hey, why confuse this kid any more than necessary? He's got homework to do! :-))) = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Help me an idiot
On 29 Apr 2001 09:06:15 -0700, [EMAIL PROTECTED] (Zina Taran) wrote: I believe, the thrust of the fries reply was the overcount in the 5*4*3*. response rather than an expression of culinary preferences. I think he was referring to order, i.e., which item was first and then second or vice versa. Order is important in permutation problems, but is not an issue in the condiment combination problem presented in the initial post. My point was that fries were not mentioned. Had he said he wanted ketchup THEN pickles NOT pickles then ketchup all would have been right with the world. Possibly, my attempt at humor in the response eluded you. How any one likes their Big Mac is beyond the scope of this newsgroup :-)) - Original Message - From: J. Williams mackeral@remove~this~first~yahoo.com To: [EMAIL PROTECTED] Sent: Sunday, April 29, 2001 10:33 AM Subject: Re: Help me an idiot On 29 Apr 2001 04:09:05 GMT, [EMAIL PROTECTED] (Eric Bohlman) wrote: I wanted that with *fries* and *ketchup*! *Not* ketchup and fries! We hear you, but fries were not included in the original problem...only the 5 condiments. But you're right, fries would be good with that! Order me one. You could make this a really nice little problem by adding in fries to the no. of possible combinations. Put onion rings in the option list too. With or without a shake would be a nice touch too. But, hey, why confuse this kid any more than necessary? He's got homework to do! :-))) = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ = = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Help me an idiot
On Sat, 28 Apr 2001 20:35:05 GMT, W. D. Allen Sr. [EMAIL PROTECTED] wrote: Five different condiments, plus no condiments, means 6*5*4*3*2*1 = 720 distinct combinations. WDA Correct me if I am wrong, but aren't you thinking of the number of permutations, i.e., all the condiments plus the no-condiment condition included? When one takes the factorial of a number of items it is the no. of items where the ordering is important. In combinations, the order of ketchup and mustard is not an issue. He could compute the combinations of 5 items, 4 at time, then 3, etc. and add them up plus the no condiment option. To help this kid with his homework, I think a better answer might be somewhere near 32 possible combinations. McDonald's has lots of varieties or so I'm told, but not that many :-))) = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Census Bureau nixes sampling on 2000 count
The Census Bureau urged Commerce Secretary Don Evans on Thursday not to use adjusted results from the 2000 population count. Evans must now weigh the recommendation from the Census Bureau, and will make the decision next week. If the data were adjusted statistically it could be used to redistribute and remap political district lines. William Barron, the Bureau Director, said in a letter to Evans that he agreed with a Census Bureau committee recommendation "that unadjusted census data be released as the Census Bureau's official redistricting data." Some say about 3 million or so people make up a disenfranchising undercount. Others disagree viewing sampling as a method to "invent" people who have not actually been counted. Politically, the stakes are high on Evans' final decision. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: MA MCAS statistical fallacy
On Mon, 15 Jan 2001 19:47:49 -0500, Rich Ulrich [EMAIL PROTECTED] wrote: Concerning the MCAS. There was a discussion last month in another Usenet group, alt.usage.english, concerning one of its math questions which was written too loosely. Here is the start of that thread. The thread has 130+ (not very interesting) entries in Deja, which is where I recovered this from. === start of Deja message. Subject: Fix the wording in this test question? Date: 12/10/2000 Author: Daniel P. B. Smith [EMAIL PROTECTED] Below is a verbatim question from a standardized math test. The concepts and mathematics are clear enough, I think. I'm presenting this is an English puzzle. 37. When Matt's and Damien's broad jumps were measured accurately to the nearest foot, each measurement was 21 feet. Which statement best describes the greatest possible difference in the lengths of Matt¹s jump and Damien's jump? A. One jump could be up to 1/4 foot longer than the other. B. One jump could be up to 1/2 foot longer than the other. C. One jump could be up to 1 foot longer than the other. D. One jump could be up to 2 feet longer than the other. END QUESTION TEXT ObPuzzle: Assume that the wording needs improvement. Assume that the concept to be tested is that "the range of real numbers for which the closest integer is 21 is the interval from 20.5 to 21.5 not including either endpoint, sometimes notated (20.5, 21.5)." What is a simple, natural wording in everyday language that would test someone's understanding of this concept while providing a single, unambiguously correct choice? Maybe, I am missing something, but think the original question and response items are quite clear and concise. I see nothing particularly "loose" about it. The essentials of a class interval used in frequency distributions seem apparent although it is subtle. For me, this appears to be an excellent question. Of course, I was not an English major either :-) = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: MA MCAS statistical fallacy
Francis Galton explained it in 1885. Possibly, the Mass. Dept. of Education missed it! Or, could it be that the same gang who brought us the exit poll data during the November election were helping them out? :-) I am wondering why they did not have a set of objective standards for ALL students to meet. Of course, it is nice to reward academically weaker districts for "improving," but the real issue may not be "improvement," rather it might be attainment at a specific level for all schools as a minimum target. A sliding scale depicting "improvement" means little if the schools in question are producting students who fall behind in math, reading comprehension, etc. Rewarding urban schools for improving probably is a good idea, but that should not mean entering a zero sum game with the "good" schools. When a given school is already "good" it naturally can't "improve" more than schools on the bottom of the achievement ladder. It seems they really should have prepared a better public announcement of results. Rather than "knocking" the high achieving schools, they should praise them justifiably. Then, noting the improvement in the large urban schools would seem positive as well. On Wed, 10 Jan 2001 21:32:43 GMT, Gene Gallagher [EMAIL PROTECTED] wrote: The Massachusetts Dept. of Education committed what appears to be a howling statistical blunder yesterday. It would be funny if not for the millions of dollars, thousands of hours of work, and thousands of students' lives that could be affected. Massachusetts has implemented a state-wide mandatory student testing program, called the MCAS. Students in the 4th, 8th and 10th grades are being tested and next year 12th grade students must pass the MCAS to graduate. The effectiveness of school districts is being assessed using average student MCAS scores. Based on the 1998 MCAS scores, districts were placed in one of 6 categories: very high, high, moderate, low, very low, or critically low. Schools were given improvement targets based on the 1998 scores, with schools in the highest two categories were expected to increase their average MCAS scores by 1 to 2 points, while schools in the lowest two categories were expected to improve their scores by 4-7 points (http://www.doe.mass.edu/ata/ratings00/rateguide00.pdf). Based on the average of 1999 and 2000 scores, each district was evaluated yesterday on whether they had met their goals. The report was posted on the MA Dept. of education web site: http://www.doe.mass.edu/news/news.asp?id=174 Those familiar with "regression to the mean" know what's coming next. The poor schools, many in urban centers like Boston, met their improvement "targets," while most of the state's top school districts failed to meet their improvement targets. The Boston Globe carried the report card and the response as a front-page story today: http://www.boston.com/dailyglobe2/010/metro/Some_top_scoring_schools_fau lted+.shtml The Globe article describes how superintendents of high performing school districts were outraged with their failing grades, while the superintendent of the Boston school district was all too pleased with the evaluation that many of his low-performing schools had improved: [Brookline High School, for example, with 18 National Merit Scholarship finalists and the highest SAT scores in years, missed its test-score target - a characterization blasted by Brookline Schools Superintendent James F. Walsh, who dismissed the report. "This is not only not helpful, it's bizarre," Walsh said. ''To call Brookline, Newton, Medfield, Weston, Wayland, Wellesley as failing to improve means so little, it's not helpful. It becomes absurd when you're using this formula the way they're using it.'' Boston School Superintendent Thomas W. Payzant, whose district had 52 of 113 schools meet or exceed expectations, was more blunt: "For the high-flying schools, I say they have a responsibility to not be smug about the level they have reached and continue to aspire to do better."] Freedman, Pisani Purvis (1998, Statistics 3rd edition) describe the fallacy involved: "In virtually all test-retest situations, the bottom group on the first test will on average show some improvement on the second test and the top group will on average fall back. This is the regression effect. Thinking that the regression effect must be due to something important, ..., is the regression fallacy." I find this really disturbing. I am not a big fan of standardized testing, but if the state is going to spend millions of dollars implementing a state-wide testing program, then the evaluation process must be statistically valid. This evaluation plan, falling prey to the regression fallacy, could not have been reviewed by a competent statistician. I hate to be completely negative about this. I'm assuming that psychologists and others involved in repeated testing must have solutions to this test-retest problem. If I'm missing the boat on the
Re: fla election stats
On 5 Jan 2001 17:32:16 -0800, [EMAIL PROTECTED] (dennis roberts) wrote: this is the perennial issue in national elections about ... if it looks like the election is sewn up from the east and south ... then what is to motivate those in the napa valley to leave their vinyards and head for the polls? i do think there are some data that roughly show that voter turnout is less out west ... compared to the east ... but, the difference is also confounded by many other factors The entire nation is not what I talked about in my post. I'm referring to voters in an individual state which is the same problem writ small. Voters in the panhandle region of Florida were confronted with electronic media calling the election before closing time. I think the annointing of a media "winner" based on exit poll data discourages "late" voting--period. In this instance a negative for both the V.P. and Bush. In close races, like the 2000 election, a few votes not cast might have changed the outcome. Is it too much to ask of the media not to call a state until the polls close? Does this infringe upon the First Amendment? These are indeed political and legal issues---not statistical ones. Statisticians should be above the fray and totally objective, right? I would be interested in research showing voter intentions in those western counties AFTER learning the election had been already called. It would be fascinating to find out what the exit pollsters revealed about those counties and if there were significant differences between the time zones factoring in prior election data, etc. What do voters think and then act on when confronted with the information that their vote will be meaningless? Or, at least the media says it would be meaningless? = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: fla election stats
On Fri, 05 Jan 2001 16:56:03 -0500, Rich Ulrich [EMAIL PROTECTED] wrote: What is your corollary issue? I don't see that you name one ... I It is simple. If your state was divided into two time zones and it was announced the election for all intents and purposes was "over," would you stand in line to vote? In particular, if you were a first time voter? Would you go out in the snow or rain to vote if it was announced by CNN the election was decided by, let's say, Philadelphia--- before you could cast a vote? Possibly, you disagree, but I think the public is not served by the major media outlets calling winners in a given state until those specific state poll sites are closed. Obviously, had the initial predictions held sway, none of us would have been the wiser. Unfortunately, the exit pollster consortium and the rush to get the story out by the electronic media contributed to public wariness about polling in general and possibly about statistical manipulations as well. Again, I urge the media to share both the methodology and the "back of the envelope" statistics used in election projections. Figuring standard errors and confidence limits can be done by the average high school student IMHO. I think the public can and will understand these issues. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
VNS polling confusion on election night
The following article appeared on CNN.com outlining the VNS exit polling errors. However, VNS believes the networks jumped the gun in predicting Florida at first for Gore, then over to Bush. The future of exit polling in close heats may be questioned more closely prior to network "predictions." December 22, 2000 Web posted at: 5:35 a.m. EST (1035 GMT) (CNN) -- An internal investigation by the polling organization that incorrectly said Al Gore won the state of Florida on election night concluded that its projections were plagued by errors all night long. But the confidential report by the Voter News Service also says that the major television networks, including CNN, bear responsibility for calling the race too soon, according to an article published in Friday's editions of The Washington Post and on the newspaper's Web site. The networks and the Associated Press created VNS in 1990 as a cost-cutting measure. CBS, NBC, ABC, CNN and Fox all relied heavily on VNS data when they first projected Gore, then George W. Bush, the winner in Florida. The networks were forced to retract both projections after it became clear the candidates were separated by only a razor-thin margin of votes. A copy of the VNS report, obtained by the newspaper, identified four major errors that contributed to what the Post called "the biggest blunder in television history." VNS had no reliable way of estimating how many absentee ballots were cast, and the final number was nearly double what the group had expected. Gore's projected lead was inflated by problems with the sampling of voters in the 45 precincts where VNS conducted exit polls. The exit poll "model" itself used by the VNS also inflated Gore's lead, because the group used Florida Gov. Jeb Bush's 1998 victory as the best predictor of how his brother would fare instead of the number of votes received by GOP presidential nominee Bob Dole in Florida in 1996. VNS was not able to correct its exit poll errors for Tampa and Miami because at 7:50 p.m. on election night, when the network calls for Gore began, those two cities had not reported any raw vote totals. At that time, the exit poll in Tampa inflated Gore's estimated lead by 16 percentage points. If any one of those four errors had not occurred, the VNS might not have called Florida for Gore, according to the report, which was written by VNS editorial director Murray Edelman. But the television networks also must shoulder responsibility for making projections without consulting VNS, according to Edelman. "It would appear that calls are being made at the minimum acceptable tolerances for risk, with very little allowance for error," he wrote. "If we are to continue in this manner, our decision procedures must be redesigned." = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: online advanced stats class where?
On Wed, 20 Dec 2000 01:31:53 GMT, "Sarah C." [EMAIL PROTECTED] wrote: I have a PhD in psychology and my school only offered basic coursework in statistics. I'd like to take an advanced applied stats class, and perhaps a psychometrics class -- preferably online. It's too specialized a topic for continuing ed programs, and I don't really want to enroll in another graduate program, just so I could take a graduate-level stats class or two... anybody got any ideas how I could find courses like this? I'm in Berkeley, California. Why not audit the class at Cal? I'm sure the stat folks there would allow you to sit in as an auditor. You probably will have to pay a fee, but would not entail enrolling in a degree program. Some schools have a visiting scholar program enabling those with advanced degrees to take advantage of the library and/or specific classes. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Census 2000
Next week the first results from Census 2000 will be released. These will be the raw state by state totals. Pending approval the Census Bureau is planning to release another set of figures developed through sampling sometime in March. These data may paint a different picture of urban residents. Pres. Bush has been asked to support the release of the latter set of data. The Supreme Court has left it to the states to decide which set of data can be used to redraw legislative districts. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Statisticians Question Gore's Recount Estimates
CNN's Web site ran an article quoting statisticians at Wisconsin and Johns Hopkins. They gave different estimates than the sort of straight line projections given by the Gore handlers. Check it out. The article was printed on 12/2/00. http://www.cnn.com/2000/ALLPOLITICS/stories/12/01/jackson.factcheck/index.html = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: NY Times article on accuracy of machine vs. hand counts
On Fri, 17 Nov 2000 15:53:58 GMT, "Robert Chung" [EMAIL PROTECTED] wrote: In today's edition of the NY Times was this article on the accuracy of machine vs. hand counts as described by the makers of vote-counting machines. http://www.nytimes.com/2000/11/17/politics/17MACH.html In summary, under ideal conditions the machines can be up to 99.99% accurate. Ideal conditions do not often apply, and in a 1975 Federal Election Commission study, it was found that 99.5% of the ballots were read accurately. The article continues, "Ultimately, industry officials said, the most precise way to count ballots is by hand." This assumes the standards for acceptable ballots have been set a priori. Would leaving it up to vote counters to "divine" what the intent of the voter was on election night be more precise? Would judgment calls on "indentations" be more precise? Stuffing the ballot box is as American as apple pie. Rascals, of course, can "stuff" a machine too I suppose. When a vote like this is too close to call and either human or mechanical errors can be operant, it seems the toss of a coin or winning a poker hand might suffice. Unfortunately, in this particular instance, the stakes are awfully high for simplistic tie-breakers. "'The important thing here is that there may be no way to get a 100 percent accurate count by a machine,' said Mr. Swartz, whose card readers are approved by the Federal Election Commission for use in punch-card voting systems. 'It is totally reasonable that the most accurate way to do it is a carefully run recount.'" --Robert Chung = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Fwd: Butterfly ballots (fwd)
In today's local paper here on the Space Coast of Florida, an elementary school teacher divided her 4th grade language arts class of varied abilities into 3 distinct groups of 11 students. Each group was asked to vote using the butterfly ballot now being questioned. One group was asked to vote for Gore, the second for Bush, and lastly for Buchanan. Without exception all the kids marked the ballots correctly. A couple of days ago, the newspaper published another similar study of 77 elementary school kids again with the same results. Interestingly, the paper endorsed V.P. Gore and supports a recount. On 14 Nov 2000 10:04:45 -0800, [EMAIL PROTECTED] (Bob Hayden) wrote: - Forwarded message from by way of Tom Lane [EMAIL PROTECTED] - From [EMAIL PROTECTED] Tue Nov 14 10:03:28 2000 Return-Path: [EMAIL PROTECTED] Received: from smtp.mathworks.com (turing.mathworks.com [144.212.95.101]) by oz.plymouth.edu (8.10.2/8.10.0) with ESMTP id eAEF3Rb98330 for [EMAIL PROTECTED]; Tue, 14 Nov 2000 10:03:27 -0500 (EST) Received: from lanet (lanet.dhcp.mathworks.com [144.212.113.27]) by smtp.mathworks.com (8.9.3/8.9.3) with SMTP id JAA14244; Tue, 14 Nov 2000 09:46:14 -0500 (EST) Message-Id: [EMAIL PROTECTED] X-Sender: [EMAIL PROTECTED] X-Mailer: QUALCOMM Windows Eudora Pro Version 4.1 Date: Tue, 14 Nov 2000 09:46:11 -0500 To: [EMAIL PROTECTED] From: [EMAIL PROTECTED] (by way of Tom Lane [EMAIL PROTECTED]) Subject: Fwd: Butterfly ballots Content-Length: 10904 Bob Smith, president-elect of the BCASA, forwarded this timely analysis that might be interesting to BCASA members. -- Tom] Date: Mon, 13 Nov 2000 17:11:26 -0700 Reply-To: Structural Equation Modeling Discussion Group [EMAIL PROTECTED] Sender: Structural Equation Modeling Discussion Group [EMAIL PROTECTED] From: rozeboom [EMAIL PROTECTED] Subject: Butterfly ballots To: [EMAIL PROTECTED] Since the voting-confusion issue has surfaced on Semnet, some of you may be interested in the following information, posted locally on our Univ. of Alberta psychology department's LAN, summarizing research done on this ballot-confusion issue by a staff member, Robert Sinclair, in amazingly fast response time. Bill R. The Butterfly Ballot Causes Confusion and Systematic Errors in Voting Behavior Robert C Sinclair University of Alberta Melvin M Mark The Pennsylvania State University Sean E Moore, Carrie A Lavis, Alexander S Soldat University of Alberta Two experiments investigated confusion and bias caused by the butterfly ballot format used in Palm Beach County in the 2000 US presidential election. In Study 1, Canadian students voted for Prime Minister of Canada on a single-column or butterfly ballot. They rated the butterfly ballot as significantly more confusing than the single-column format; however, they made no voting errors. Study 2 replicated the confusion effect with a nonstudent sample. Of greater importance, participants made errors only on the butterfly ballot. The butterfly ballot causes confusion and systematic errors in voting. The issue of systematic bias as a result of ballot format has become the focus of much controversy surrounding the outcome of the recent presidential election in the United States. Specifically, people have argued that the format of the ballot in Palm Beach County led to confusion and caused people who intended to vote for Al Gore to mistakenly cast votes for Pat Buchanan or punch two holes resulting in a voided ballot. We conducted two experimental studies to address this issue. On Wednesday, November 8, 2000 (the day after the presidential election), we had Canadian college students vote for Prime Minister of Canada using a single-column ballot format or a dual-column, butterfly format (analogous to the Palm Beach County-style ballot). We expected that students would rate the butterfly style as more confusing than the single-column format. However, it was unclear whether students, who are familiar with confusing optical scoring forms, would make errors on the ballot. Participants Participants were 324 introductory psychology students from two classes at University of Alberta. All were volunteers who participated in order to partially fulfill a course requirement. Procedure Ballot Construction. The ballots contained the names of the leaders of 10 Canadian political parties and space for a write in candidate. One ballot used a single-column format. The second was designed to emulate the dual-column, butterfly format used in Palm Beach County (at the time this study was conducted, to the investigators knowledge the actual ballot was not available on the web or in print media, and the ballot was constructed after seeing it displayed for a brief period on CNN). The butterfly ballot was designed so that the leaders of
Re: Fwd: Butterfly ballots (fwd)
On Tue, 14 Nov 2000 22:17:31 GMT, Ronald Bloom [EMAIL PROTECTED] wrote: J. Williams [EMAIL PROTECTED] wrote: In today's local paper here on the Space Coast of Florida, an elementary school teacher divided her 4th grade language arts class of varied abilities into 3 distinct groups of 11 students. Each group was asked to vote using the butterfly ballot now being questioned. One group was asked to vote for Gore, the second for Bush, and lastly for Buchanan. Without exception all the kids marked the ballots correctly. A couple of days ago, the newspaper published another similar study of 77 elementary school kids again with the same results. Interestingly, the paper endorsed V.P. Gore and supports a recount. Would the group of kids doing a post-hoc experiment be biased inasmuch as the nature of the problem at hand may have become common-knowledge by now; even among kids; and so one would be forewarned of the error-mode in question, and be much less likely to fall into that mode of error? At any rate, what inference am I being prompted to draw here? That the people who claimed to have been confused were either (a) ignoramuses or (b) changing their tune after the fact? Is there some more generous interpretation, (c), say? Sure, those who complained were truly confused. BTW, it is my understanding each voter is allowed 2 additional ballots should a given voter make an error. If voters were denied these additional "attempts," then something is indeed very wrong. I am puzzled why in overwhelmingly Democratic precincts, those who complained were denied the additional ballots. Needless to say, it is a troubling situation. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Polls: Errors on Prime Time - NOT AN ERROR
Are you saying that only Gore supporters could not figure out the ballot? Plus, only Gore voters were too timid to ask for assistance or for a new ballot? :-)) Could it be that they are complaining ex post facto when confronted with an unpopular result? :-) Apparently, upon leaving the polling place, they at first must have "misled" the exit pollsters! Only later after the polls closed they remembered their "error." Hm. On Mon, 13 Nov 2000 08:42:36 -0500, SSCHEINE [EMAIL PROTECTED] wrote: Actually, the exiting polls got it right!!! Remember, a lot of people left the polling booth thinking that they had voted for Gore, when they had actually messed up their ballot. Based on who they thought that they had voted for, they informed the exit pollers who called it for Gore. Sam ** Samuel M. Scheiner Div. Envir. Biol. (Rm 635) National Science Foundation 4201 Wilson Blvd. Arlington, VA 22230 Tel: 703-292-7189 Fax: 703-292-9065 Email: [EMAIL PROTECTED] = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Polls: Errors on Prime Time
It appeared at first it was Gore winning Florida. No, wait. It's Bush. He's the next President. No, now it's too close to call. All of it based on the exit poll consortium used by the networks. This appears to be the reason all the networks got it wrong. To save money, the networks pool their resources and receive one set of predictions. Now, the talking heads are blaming (pick one): bad data, goofy statisticians, precinct fraud, and on and on. As I have indicated in earlier years, these telephone polls and "exit" interviews are very troublesome --- particularly in close races. How many people are willing to detail their "secret" ballot to a stranger whether on the phone or in person? I think there are many who either refuse or ignore such requests.I know I would. It is no one's business how I voted. Precinct history is not etched in stone either. Sampling and the consequent polls have taken a hit. I suppose I can understand how the general public and various courts are concerned about how the Census should be conducted vis a vis sampling instead of actual head counts. Cynicism about sampling and polling will be alive and well after this election---regardless of who wins. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Polls and caller ID
On Mon, 25 Sep 2000 11:12:44 -0400, Bob Wheeler [EMAIL PROTECTED] wrote: Are pollsters having special difficulties this time around due to caller ID? I'd think that the nonresponse would be hard to quantify. Is there a web site that spells out the methodologies of the various polling groups? -- Bob Wheeler --- (Reply to: [EMAIL PROTECTED]) ECHIP, Inc. They are also limited by the vast numbers of potential voters who use simple answering machines to avoid telemarketing. I doubt if many will return a call just to please a pollster. Personally, I have many reservations about the sampling procedures in telephone political polling often dubbed as "scientific." Why not check out the time of day of the poll, the zip codes of those queried, percentage of nonresponses, how hangups and not-at-homes, etc. are handled by the polling organization. If all this information is proprietary or "secret," it is hard to ascertain validity. Much of what passes for "scientific" is back of the envelope statistics IMHO. Oh well, it sells papers and gives talking heads something to mull over. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: consulting services for graduate students?
If the agency plans the research, analyzes the data, and edits the results, what does the student do? Why have a committee waste university time if an agency is going to handle the tough chores? Back in the ice age when I was a graduate student in Ann Arbor, the Ph.D. dissertation was expected to be an original piece of research. The desired outcome was a scholar who could do independent work that could stand up to peer review. Please let me know if this is no longer the case. Most major research universities have stat labs staffed to help doctoral candidates achieve the aforementioned objectives. Also, usually the writing of the thesis is preceded by a research proposal outling the future shape of the independent work. Would the agency provide a proposal too? IMHO, the student after doing the research over several years on one topic should know the details of the study better than the committee members or anyone else. If a hired gun does the work, they know it, but the studen/customer may have trouble explaining it later on at the oral examination or in the future after graduating. Maybe I am off base, but I think when an outside agency for hire does all the work, attribution is least of a committee chair's worries. In article [EMAIL PROTECTED], [EMAIL PROTECTED] (EAKIN MARK E) wrote: A graduate student showed me an email from a web-based service that offers to help graduate students plan their study, analyze the data, and edit the results. He was concerned about the ethics of using this service. In my opinion, graduate students have always received this kind of assistance from their committee members and fellow students. My only concern would be the amount of assistance provided and the inclusion of appropriate citation(s). But for me this leads to the question of how much is too much? Any comments? Mark Eakin Associate Professor Information Systems and Management Sciences Department University of Texas at Arlington [EMAIL PROTECTED] or [EMAIL PROTECTED] === This list is open to everyone. Occasionally, people lacking respect for other members of the list send messages that are inappropriate or unrelated to the list's discussion topics. Please just delete the offensive email. For information concerning the list, please see the following web page: http://jse.stat.ncsu.edu/ ===
Re: Demand for a product
Before an answer to your query can be completed, more information is required. First, is the 25 figure really the sample or is it the population of potential customers? If it is the latter, simply question all 25 with a mix of Likert Scale and "Yes/No" responses. With a high tech product, visiting with the target customer's executives might be the best solution to gauge interest. Second, if the 25 is indeed a sample, what is the size of the potential customer base (population). Third, a good visit to a proximate university library and browsing through a good market research text will explain many of the questions you ask. Since the "25" appears fixed and not a random sampling from a given population, it makes a difference in looking at it statistically. It is called a "convenience" sample, i.e., these 25 were already in place or selected because they are cooperative. Those 25 might differ from other customers in an important way. Unless the 25 number is sine qua non, why not determine the total number of potential customers, randomly select a sample from them and then analyze the results with standard statistical procedures? In article 002901bf63f2$35665e80$21c0@grant, [EMAIL PROTECTED] (Grant) wrote: Dear Edsaters, I have a client who would like to determine the demand for a very high-tech product and would like the results to be rigorous as they will be used to convince investors of the need for such a product. The problem is that the sample size is only about 25. Besides frequency counts and percentages how else can one analyses the results to show that there is a demand for the product? Any suggestions on important questions that need to be asked will also be welcome. I have read that a simple yes/no scale is better that a 5 point likelihood scale for demand type questions. Any thoughts? Kind regards Grant
Re: y2k confound
In article [EMAIL PROTECTED], [EMAIL PROTECTED] (dennis roberts) wrote: happy new year to everyone ... hope your y2k +1 year is great! now, the y2k scare provides us with an excellent example of confounds (more or less) .. consider the following: Time One: lots of hype about "potential" disasters related to y2k ... (PRETEST) Time Two: billions of $$$ spent on "fixing" y2k "problems" (TREATMENT) Time Three: world notes relatively few y2k problems ... (POSTTEST) so ... did the "treatment" lead to the observation of "few problems"? The only thing you're missing is a control group (one with a "treatment" that didn't spend billions on a fix) and you'd really have something here. :-)) I'm wondering if those spending/earning the billions are congratulating themselves on so "few problems" (We fixed that just right!!!) or if the problems existed in the first place. Now, if we'd only had a control group.
Re: transcript
Many businesses and institutions hiring key personnel ask applicants to instruct his/her university to send an official transcipt with seal directly to the employer. This is not so much to ponder over a "B" or an "A" in various courses, but to determine the person did indeed graduate with a given degree. Every now and then one reads about a poseur who claimed degrees, graduation, etc., and later it is discovered the person falsified credentials. Transcripts, from this perspective, protects the forthright applicant and a potential employer. In article [EMAIL PROTECTED], [EMAIL PROTECTED] (dennis roberts) wrote: html At 12:09 PM 12/28/99 -0500, Herman Rubin wrote:br br blockquote type=cite citeWhat is definitely NOT needed is a quot;transcriptquot;.nbsp; Those whobr think that this record indicates what the student knows andbr can do is at least badly mistaken. /blockquotebr br well, whether it is called a transcript or something else ... we DO need some record of what the student did (i don't think having the student say ... quot;I went to Purdue ... quot; would be sufficient)... and, what courses a student took ... and even grades are helpful . br br i don't think anyone would equate grades on the transcript with what the student knows but ... i will be a dime to a penny that if you saw a transcript for two students (from comparable institutions) where one got mostly Cs ... and the other got mostly As ... that we CAN assume that one has learned alot more than the other ... br br br div--/div div208 Cedar Bldg., University Park, PA 16802/div divAC 814-863-2401nbsp;nbsp;nbsp; Email a href="mailto:[EMAIL PROTECTED]" EUDORA=AUTOURLmailto:[EMAIL PROTECTED]/a/div divWWW: a href="http://roberts.ed.psu.edu/users/droberts/drober%7E1.htm" EUDORA=AUTOURLhttp://roberts.ed.psu.edu/users/droberts/drober~1.htm/a/div FAX: AC 814-863-1002 /html
Re: adjusting marks
I assume she intends to move all marks up or down in tandem. I assume too that the marks themselves are quantitative along some sort of continuum. Regardless, the easiest thing would be to rank order them and make a decision where the cutoff lines for A's, B's, etc.make sense. I don't see this as a statistical problem per se. You could graph the scores with a scatterplot or histogram to determine the shape of the distribution. She could visually inspect the plot and see if the distribution is bell-shaped, uniform, skewed, etc. If the data so indicate, one could do Z scores and find out the distance from the mean, percentile rank, etc., but IMHO this problem can be better solved by intuition, viz., looking at the data, drawing rational cutoff lines and at the same time being fair to the students. In article jhD74.6313$[EMAIL PROTECTED], "Generic" [EMAIL PROTECTED] wrote: My wife wants to adjust marks for a course she is marking. Does someone have a formula or something for using a bell curve to move them up or down? I have done this sort of thing about 15 years ago, but I can't remember any of it!
Re: dissertation
One of the first things to do is to pose your queries with a senior faculty member with whom you are acquainted. Perhaps, you might even boldly bounce a few subject/topic areas for your thesis with him/her. Some professors have favorite dissertations "on the shelf" portraying what has been acceptable in the past. Take a look at those to get a general idea. Usually, university graduate libraries will have dissertations and/or abstracts for visual review as well. Many graduate schools have a step by step manual or handbook on the various procedures for the progression toward the doctorate starting with obtaining a committee chair, writing an acceptable proposal and ending with a successful defense of the thesis. Doing independent research is a lonely task and you must be prepared for a struggle right from the start. There are lots of hurdles and roadblocks, but with patience and diligence plus a modicum of talent you'll make it. Don't get discouraged. By the time you are finished, you'll know more about that dissertation than anyone else if all goes correctly. You probably have wondered how some of us (faculty) ever made it through the system. In my case, the same way you will...bumbling and stumbling. Good Luck. j. williams In article 838sqb$26ho$[EMAIL PROTECTED], "J.L." [EMAIL PROTECTED] wrote: Hello all -- I am a PhD student in biostats. who will be starting the dissertation process in about a year and a half. Could anyone direct me to some useful books/web sites/other references on beginning, researching, writing the dissertation? Most of the books I have found so far seem to be written more for students in non-science related fields. TIA,
Re: Help for my dissertation
First, check to see if your school doesn't have a stat lab available. Most major universities have a site where graduate students and others involved in empirical research can get free assistance. Often, it is in the form of anothe, but more advanced, graduate student, but many of these folks are perfectly capable of looking over your proposal and can give helpful hints. Second, you might want to consider adding a statistically knowledgeable person to your committee if it is not too late. If I were you, I would get the statistical guidance BEFORE you start collecting data or whatever methodology you envision. Lastly, you can go to the statistics department at your school and get the names of consultants available for looking over your materials. Good Luck j. williams In article 82j1a2$6s3$[EMAIL PROTECTED], [EMAIL PROTECTED] wrote: I am a 3rd year student carrying out resaerch for my dissertation. I require help with stats - primarily to confirm that I amusing the correct methods to test my hypothesis and secondly to understand them once I have collected my data. I am prepared to pay for some ones time if they could help me. Is there anyone out there that could help? Sent via Deja.com http://www.deja.com/ Before you buy.
Re: We need help with our Stats project!
If this is for a statistics course assignment, you should read a little bit about convenience or accidental sampling in a research design text at your school's library. Nonprobability sampling provides no way to forecast that each element in your target pop. will be adequately estimated or represented. To put a good spin on it, you could say the sample consisted of 1000 individuals who either self-selected themselves or their friends. Before wasting time collecting and tabulating these data, why not do just a little homework and do it right...the first time. Secondly, press your statistics professor/advisor about probability vs. nonprobability sampling. How samples are drawn and selected are the bedrock of survey research. Running crossbreaks and contrived descriptive statistical analyses mean nothing if the sample does not represent the population. Good luck. In article 81a1pf$tvr$[EMAIL PROTECTED], [EMAIL PROTECTED] wrote: We are college students who are conducting a survey about the types of internet browser people use. Our target size is 1000. Please participate by filling out the following six questions and pass this to your friends. Your help is much appreciated! -- Gender (M/F): Age: Most frequently used browser (Netscape/IE/AOL/Others): Type of Internet Service Provider (ADSL/Cable/Dial Up/Network Others): Average hours of surfing per week: Browsing experience (in months/years): -- When you're done, please send this back to [EMAIL PROTECTED] Sent via Deja.com http://www.deja.com/ Before you buy.
