Re: Factor Analysis
Dear Haytham, other issue concern with a measure of the latent construct is the unidimensionality. Hair et alli(1998): unidimensionality is an assumption underlying the calculation of reliability and is demonstraded when indicators of a construct have acceptable fit on a single-factor(one-dimensional) model.(...) The use of reliability measures, such Cronbach´s alpha, does not ensure unidimensionality but instead assumes it exists. The researcher is encouraged to perform unidimensionality tests on all multiple-indicator constructs before assessing their reliability. This reference is very important: Gerbing, David W., Anderson, James C. An updated paadigm for scale development incorporating unidimensionality and its assesment. Best regards, Alexandre Moura. P.S. Please accept my apologies for my English mistakes. - Original Message - From: haytham siala [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, June 15, 2001 5:40 PM Subject: Factor Analysis Hi, I will appreciate if someone can help me with this question: if factors extracted from a factor analysis were found to be reliable (using an internal consistency test like a Cronbach alpha), can they be used to represent a measure of the latent construct? If yes, are there any references or books that justify this technique? = 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: Factor Analysis
The complete reference: Gerbing, David W., Anderson, James C. An updated paradigm for scale development incorporating unidimensionality and its assesment. Journal of Marketing Research. Vol. XXV (May 1988). Alexandre Moura. - Original Message - From: Alexandre Moura [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Saturday, June 16, 2001 9:26 AM Subject: Re: Factor Analysis Dear Haytham, other issue concern with a measure of the latent construct is the unidimensionality. Hair et alli(1998): unidimensionality is an assumption underlying the calculation of reliability and is demonstraded when indicators of a construct have acceptable fit on a single-factor(one-dimensional) model.(...) The use of reliability measures, such Cronbach´s alpha, does not ensure unidimensionality but instead assumes it exists. The researcher is encouraged to perform unidimensionality tests on all multiple-indicator constructs before assessing their reliability. This reference is very important: Gerbing, David W., Anderson, James C. An updated paadigm for scale development incorporating unidimensionality and its assesment. Best regards, Alexandre Moura. P.S. Please accept my apologies for my English mistakes. - Original Message - From: haytham siala [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, June 15, 2001 5:40 PM Subject: Factor Analysis Hi, I will appreciate if someone can help me with this question: if factors extracted from a factor analysis were found to be reliable (using an internal consistency test like a Cronbach alpha), can they be used to represent a measure of the latent construct? If yes, are there any references or books that justify this technique? = 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/ = = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Normality in Factor Analysis
Hi, I have a question regarding factor analysis: Is normality an important precondition for using factor analysis? If no, are there any books that justify this. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Probability Of an Unknown Event
It's been years since I was in school so I do not remember if I have the following statement correct. Pascal said that if we know absolutely nothing about the probability of occurrence of an event then our best estimate for the probability of occurrence of that event is one half. Do I have it correctly? Any guidance on a source reference would be greatly appreciated! Thanks, WDA [EMAIL PROTECTED] end = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Marijuana
There is medical research that shows marijuana is more lethal than tobacco regarding lung cancer. Maybe there is a correlation between lung cancer susceptibility and heart attacks? We know there is for tobacco! WDA end Paul Jones [EMAIL PROTECTED] wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... There was some research recently linking heart attacks with Marijuana smoking. I'm trying to work out the correlation and, most importantly, its statistical significance. In essence the problem comes down to: Of 8760 hours in a year, 124 had heart attacks in them, 141 had MJ smokes in them and 9 had both. What statistical tests apply? Most importantly, what is the statistical significance of the correlation between smoking MJ in any hour and having a heart attack in that same hour? What is the probablity that the null hypothesis (that smoking marijuana and having a heart attack are unrelated) can be rejected? How reliable are the results from a dataset of this size? I'm not very literate in maths and stats - please help me out someone. I'm interested in this research from the perspective of medicinal marijuana. Thanks and take care, Paul All About MS - the latest MS News and Views http://www.mult-sclerosis.org/ = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Normality in Factor Analysis
In sci.stat.consult haytham siala [EMAIL PROTECTED] wrote: I have a question regarding factor analysis: Is normality an important precondition for using factor analysis? It's necessary for testing hypotheses about factors extracted by Joreskog's maximum-likelihood method. Otherwise, no. If no, are there any books that justify this. Any book on factor analysis or multivariate statistics in general. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Marijuana
In article XhRW6.14316$[EMAIL PROTECTED], W. D. Allen Sr. [EMAIL PROTECTED] wrote: There is medical research that shows marijuana is more lethal than tobacco regarding lung cancer. Thanks for playing, but sorry, no. There's a lot of research which says a lot of different things about marijauna's deleterious effects on the lungs. Off the top of my head: A Berkeley study of the late '70s concluded that marijuana is one-and-a-half times as carcinogenic as tobacco. This assesment took into account _only_ quantities of tar. Tar, while a carcinogen, is not the primary cancer-causing agent in tobacco, or even close; polonium 210 and lead 210 are considerably more hazardous and conspicuously absent from marijuana. Add to this the fact that marijuana smokers are unlikely to consume nearly as much net weight smokable material as tobacco smokers, and you're talking apples and oranges. Actual tests on real live people bears this out. Multiple population samples show no correlation between marijuana use exclusive of tobacco use and lung cancer: Tashkin, D.P. et al, Longitudinal Changes in Respiratory Symptoms and Lung Function in Non-smokers, Tobacco Smokers, and Heavy, Habitual Smokers of Marijuana With or Without Tobacco, pp 25-36 in G. Chesher et al (eds), Marijuana: an International Research Report, Canberra: Australian Government Publishing Service (1988). Sherrill, D.L. et al, Respiratory Effects of Non-Tobacco Cigarettes: A Longitudinal Study in General Population, International Journal of Epidemiology 20: 132-37 (1991). Fligiel, S.E.G. et al, Bronchial Pathology in Chronic Marijuana Smokers: A Light Electron Microscope Study, Journal of Psychoactive Drugs 20:33-42 (1988). Maybe there is a correlation between lung cancer susceptibility and heart attacks? We know there is for tobacco! Well, inhaling smoke of _any_ sort actually puts some strain on your heart. I believe specific toxins in tobacco exacerbate the problem, but it's present for all types of smokables. Of course, we're very off-topic here. Anyone want to crosspost this thread to sci.med.*, or talk.politics.drugs? +--First Church of Briantology--Order of the Holy Quaternion--+ | A mathematician is a device for turning coffee into | | theorems. -Paul Erdos | +-+ | Jake Wildstrom| +-+ = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
!!! We can pass the Speed of Light for sure !!! NEW MATH
!!! We can pass the Speed of Light for sure !!! NEW MATH
=== This is an interesting open message. Since it is extremely
controversial with today's understandings, you may treat it with open
mind, and use your own judgement.===
!!! We can pass the Speed of Light for sure !!! NEW MATH
1. Today's physics assumes that the forces a particle receives from
the fixed field sources are constant during its moving.
Unfortunately, this prior assumption is totally WRONG! The force that
a particle receives from the fixed field source is NOT CONSTANT. It
will vary with the moving speed v of this particle. The formula will
be:
F = (1-v^2/c^2)Fo
Where Fo is the force which a particle receives at its rest state, and
the c is the speed of light;
2. From point 1, if a particle's velocity approaches to the speed of
light c, this particle then will receive NO force. Therefore, this
particle will have NO acceleration at that time, OF COURSE this
particle can not pass the speed of light;
3. If we use other force sources, for example imaging if this particle
like a jet, then we can broken the speed of light c easily. In one
word:
!!! There is NO speed limit, and we can pass the speed of light just
like we pass the speed of sound !!!
4. The mass of a particle will NOT change during its moving. The
formula:
m = m0 / (1-v^2/c^2)^(1/2)
is wrong;
5. The time will definitely NOT change during its moving. The formula:
t = t0 * (1-v^2/c^2)^(1/2)
is also wrong;
6. Actually, point 4 and 5 are come from the following:
F = m0 dv/d(t0)
(1-v^2/c^2)Fo = m0 dv/d(t0)
Fo = [m0 dv/d(t0)] / (1-v^2/c^2)
Fo = [m0/(1-v^2/c^2)^(1/2)] * {dv/d [t0 (1-v^2/c^2)^(1/2)]}
Comparing with the general form:
Fo = m dv/dt
Then we get these two funny formulas:
m = m0 / (1-v^2/c^2)^(1/2)
and
t = t0 * (1-v^2/c^2)^(1/2)
They are only the mathematical terms and no real physical meanings.
--- How can we use them as our principles ?!
7. In one word
!!! -- There exists NO relativity -- !!!
One may ask that why most of the past and today's experiments have
strongly supported the relativity?
=Answer=: There really exist some relativity results, BUT they are
NOT coming from the relativity, they indeed comes from the following
force's FACTOR:
1-v^2/c^2
You may go to the following website to get the details:
http://www.yun-qi.com
=== EXPERIMENTS HINTS ===
If we set S = eBR/(mc), where e is the electron charge, R is the
cyclotron radius that a charged particle bending in the magnetic field
B, m is the rest mass of this particle, and c is the speed of light.
For the fixed magnetic field force, say Lorentz force, we have:
Today's Theory:
F = evB
S = (v/c) / (1-v^2/c^2)^(1/2)
v/c = 1 / (1+1/S^2)^(1/2)
Yun-Qi Theory:
F = (1-v^2/c^2) (Lorentz Force) = (1-v^2/c^2) evB
S = (v/c) / (1-v^2/c^2)
v/c = [1+1/(4S^2)]^(1/2) - 1/(2S)
These two theories will give the totally different data of the real
speeds for the certain S, and will give the huge differences of the
velocity changes for the different S.
For example, if we set the cyclotron radius is equal to one (1), the
relativity theory will teach us that the particle's velocity is
0.707106781c, BUT Yun-Qi theory will predict that its real velocity
will actually be 0.618033988c --- the exact Golden Number. The net
difference is 0.089072793c. See, there exists a big difference here.
If you are interested, you can check --- http://www.yun-qi.com --- for
the detailed data of the huge differences.
== The following is the interesting abstract from the article which
includes the above theory ==
This article will give the totally new views from any aspects we know
today, so it's better to treat it with open mind. In this paper, I
have derived from ``non--nothing --- to the following
most astounding results:
1. Ohitor Algebra;
2. Integration;
3. Differentiation;
4. Ohitor Bexl;
5. V-Space;
6. A-Space;
7. Most of Mechanics Laws;
8. Gravity Law --- is not clearly shown, but in it;
9. Many New Laws, like spin, mota, ..
All in a 41-page article. Here are some new concepts: ohitor, bexl,
mota, ... I just can't use today's words to express them.
If you are interested, you can get this paper from above website, or
you can download it directly from the followings:
1. For Acrobat Reader: --- http://www.yun-qi.com/Yq01.pdf
2. For DVI File: - http://www.yun-qi.com/Yq01.dvi
3. For PostScript File: -- http://www.yun-qi.com/Yq01.ps
=
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