Re: Rates and proportions

2000-06-22 Thread Donald Burrill
On Wed, 21 Jun 2000, Dale Berger wrote: Yet, p=0 is a special case where an outcome is impossible. A reasonable confidence interval for p should not include zero if the outcome has been observed in a sample. Not so? I am unable to reconcile this assertion with the fact that the only

Re: weapons politics, USA

2000-06-22 Thread lambert
In article nHG35.10954$[EMAIL PROTECTED], "Shawn Wilson" [EMAIL PROTECTED] wrote: [EMAIL PROTECTED] wrote in message Have you successfully completed even one course in statistics? Six, three at the graduate level in the specific field of econometrics and three undergrad (including one

Re: Rates and proportions

2000-06-22 Thread Robert Dawson
On Wed, 21 Jun 2000, Dale Berger wrote: Yet, p=0 is a special case where an outcome is impossible. A reasonable confidence interval for p should not include zero if the outcome has been observed in a sample. Not so? and Donald Burrill replied: I am unable to reconcile this

Re: differences between groups/treatments ?

2000-06-22 Thread Gene Gallagher
Rich Ulrich wrote: These are not quite equivalent options since the first one really stinks -- If you are considering drawing conclusions about causation, you need *random assignment* and the two Groups of performance are the furthest thing from random. Let's see: the simple notion of

Re: Comments about my syllabus

2000-06-22 Thread SAlbert
Stephen, I would also characterize the syllabus as too ambitious -- by far. Your students are probably scared of statistics, and overwhelming them will only make it worse. Unless you see a special need for it, for example, I'd omit time series in a first course! You might want to look at

Re: differences between groups/treatments ?

2000-06-22 Thread Rich Strauss
At 04:31 PM 6/22/00 +, Gene Gallagher wrote: This pattern was described in an obit about two-three years ago in the NY Times. A statistician's obit noted that he'd found a flaw in the Israeli air force's training program. Apparently, the Israeli air force was punishing the worst performers

Re: differences between groups/treatments ?

2000-06-22 Thread dennis roberts
regression to the mean is not necessarily appropriate when looking at pretest scores ... and then gain or improvement ... if we had parallel tests ... one for pre and one for post ... when nothing happens inbetween ... then maybe so ... please see a short summary of this scenario ... applied

Re: differences between groups/treatments ?

2000-06-22 Thread lthayer
Look up the topic regression to the mean. This means that of values measured several times , when extremes are revisited they can be at a more typical value. In article 8itf0t$a68$[EMAIL PROTECTED], Gene Gallagher [EMAIL PROTECTED] wrote: Rich Ulrich wrote: These are not quite equivalent

RE: Rates and proportions

2000-06-22 Thread Rodney Carr
Here's what I got for the confidence interval: Let n = sample size, K = number of successes, p = sample proportion (=K/n), pi = true proportion. If n = 1250 and K = 1 (p = 1/1250), we can be 95% sure that pi about 0.41 (small-sample one-sided 95% confidence interval using the binomial

samples with no preference in it

2000-06-22 Thread sig
I took a sample to determine if users preferred one of 3 different designs (A, B, and C). Of the 740 people sampled, 300 replied "no preference", 160 preferred prototype A, 130 B, and 150 C. Is there a significant difference between the protoypes? If so, which ones? Which test do I use? How do

ANOVA, Robustness, and Power

2000-06-22 Thread Alex Yu
ANOVA is said to robust against assumption violations when the sample size is large. However, when the sample size is huge, it tends to overpower the test and thus the null may be falsly rejected. Which is a lesser evil? Your input will be greatly appreciated.

Good News from College Broadcast!

2000-06-22 Thread GoodNews
Title: Untitled Document June 21, 2000