Correlation,Social Psychology N

2002-02-22 Thread christian
. a Product/Company) and calculate the different correlations dependend from the thing is rated as 1./2./3. or all togehter! Not a surprise for me are the different values in correlation, but make the use of correlations for this doubtful. What is more a cause for this results'S ? (1) The small N's (2

Re: can multicollinearity force a correlation?

2002-02-20 Thread Wuzzy
My tentative conclusion is that your 2% effect really is a small one; it should be difficult to discern among likely artifacts; and therefore, it is hardly worth mentioning I agree to me it makes sense as well: fasting insulin should have more to do with error and genetics than food

Re: can multicollinearity force a correlation?

2002-02-19 Thread Rich Ulrich
On 18 Feb 2002 16:29:27 -0800, [EMAIL PROTECTED] (Wuzzy) wrote: You should take note that R^2 is *not* a very good measure of 'effect size.' Hi Rich, you asked to see my data, - I don't remember doing that - i've posted the visual at

Re: can multicollinearity force a correlation?

2002-02-18 Thread Wuzzy
http://www.accessv.com/~joemende/insulin2.gif Appologies, i also forgot to divide the KCAL in food by the 31 as this represents kcal. It seems to me logical to advise decreasing food intake and increasing physical activity to improve insulin sensitivity. I would probably avoid reporting the

Re: can multicollinearity force a correlation?

2002-02-18 Thread Wuzzy
You should take note that R^2 is *not* a very good measure of 'effect size.' Hi Rich, you asked to see my data, i've posted the visual at the following location http://www.accessv.com/~joemende/insulin2.gif note that the r^2 is low despite the fact that it agrees with common sense: Insulin

Re: can multicollinearity force a correlation?

2002-02-18 Thread Juha Puranen
Wuzzy wrote: http://www.accessv.com/~joemende/insulin2.gif Appologies, i also forgot to divide the KCAL in food by the 31 as this represents kcal. It seems to me logical to advise decreasing food intake and increasing physical activity to improve insulin sensitivity. I would probably

Re: can multicollinearity force a correlation?

2002-02-15 Thread Rich Ulrich
[ snip, previous problem] This is similar to a problem I have come across: the measurement of a serum value against exposure. My theory is that they are correlated. But the data says that they have an R^2 of 0.02 even though the p-value for the beta is p=1E-40 (ie. zero). As you

Re: can multicollinearity force a correlation?

2002-02-12 Thread Wuzzy
low-fat vegan diet would be close). However, the incidence of heterozygous familal hypercholesterolemia is only 1:500,000, so this exposure contributes little to the variance in serum cholesterol in the population; its r^2 would be small. -Jay Thanks, This is similar to a problem I have

Re: can multicollinearity force a correlation?

2002-02-09 Thread Wuzzy
And that sounds impossible. I suspect a programming error. -Jay you're right i programmed a food database incorrectly but i've redone it and yep the correlation was only 0.20 for kcal or so. it is hard to program a database *into* another database easy to make errors.. i've made many

Re: can multicollinearity force a correlation?

2002-02-09 Thread Wuzzy
Jay Tanzman [EMAIL PROTECTED] wrote in message news:a42e88$1bthp5$[EMAIL PROTECTED]... Wuzzy [EMAIL PROTECTED] wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... It is because I am validating a 24hr dietary recall questionnaire using a food frequency questionnaire: It was

Re: can multicollinearity force a correlation?

2002-02-09 Thread Jay Tanzman
Wuzzy [EMAIL PROTECTED] wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... And that sounds impossible. I suspect a programming error. -Jay you're right i programmed a food database incorrectly but i've redone it and yep the correlation was only 0.20 for kc

Re: can multicollinearity force a correlation?

2002-02-08 Thread Jay Tanzman
ly I got a perfect correlation between the two, you would think that the 24hr would be at least a bit attenuated but I got a perfect correlation or error And that sounds impossible. I suspect a programming error. -Jay = Inst

Re: can multicollinearity force a correlation?

2002-02-07 Thread Herman Rubin
In article [EMAIL PROTECTED], Wuzzy [EMAIL PROTECTED] wrote: Is it possible that multicollinearity can force a correlation that does not exist? I have a very large sample of n=5,000 and have found that disease= exposure + exposure + exposure + exposure R^2=0.45 where all 4 exposures

Re: can multicollinearity force a correlation?

2002-02-07 Thread Rich Ulrich
to my question is No.. Well, I think I speak for several statisticians when I say that we still don't know what you refer to as 'multi collinearity'. Do you mean 100%, as in your question? What *are* you asking? Multicollinearity cannot force a correlation. It turns out that ONE

Re: can multicollinearity force a correlation?

2002-02-07 Thread Wuzzy
Hi Rich, okay i'll post the reason why I ask: It is because I am validating a 24hr dietary recall questionnaire using a food frequency questionnaire: as someone else pointed out i got an error, also a perfect correlation for pearsons. it is much more complicated than

Re: can multicollinearity force a correlation?

2002-02-06 Thread J.Russell
To: [EMAIL PROTECTED] Date sent: 5 Feb 2002 18:15:00 -0800 From: [EMAIL PROTECTED] (Wuzzy) Organization: http://groups.google.com/ Subject:Re: can multicollinearity force a correlation? In my own defense: I was asking a simple

Re: can multicollinearity force a correlation?

2002-02-06 Thread Jay Warner
, turns out that the answer to my question is No.. Multicollinearity cannot force a correlation. It turns out that ONE of the variables *was* correlated With R^2=0.45 and so multicollinearity had no effect on overall R^2. I'm sure no-one is interested in my data as it has nothing to do

can multicollinearity force a correlation?

2002-02-05 Thread Wuzzy
Is it possible that multicollinearity can force a correlation that does not exist? I have a very large sample of n=5,000 and have found that disease= exposure + exposure + exposure + exposure R^2=0.45 where all 4 exposures are the exact same exposure in different units like ug/dL or mg/dL

Re: can multicollinearity force a correlation?

2002-02-05 Thread Kevin C. Heslin
: Is it possible that multicollinearity can force a correlation that does not exist? I have a very large sample of n=5,000 and have found that disease= exposure + exposure + exposure + exposure R^2=0.45 where all 4 exposures are the exact same exposure in different units like ug/dL or mg/dL

RE: can multicollinearity force a correlation?

2002-02-05 Thread Simon, Steve, PhD
Title: RE: can multicollinearity force a correlation? Is it possible that multicollinearity can force a correlation that does not exist? I have a very large sample of n=5,000 and have found that disease= exposure + exposure + exposure + exposure R^2=0.45 where all 4 exposures

Re: can multicollinearity force a correlation?

2002-02-05 Thread Wuzzy
You made a model with the exact same exposure in different units, which is something that no one would do, Hehe, translation is don't post messages until you've thought them through. Anyway, turns out that the answer to my question is No.. Multicollinearity cannot force a correlation

Re: can multicollinearity force a correlation?

2002-02-05 Thread Wuzzy
In my own defense: I was asking a simple question: will highly correlated cause an irregularly high R^2. My answer to my own question is no it can't.. No-one here was able to give me this answer and I believe it is correct: if your sample is large enough,(as mine is) then no,

Re: correlation of dependent variables

2002-02-01 Thread DELOMBA
Isn't it the same as getting the variance of the product of the independant uncorrelated variables A B ? Y. John Smith [EMAIL PROTECTED] wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... If I have 3 variables defined as follows: A, B as independent, uncorrelated values of 0 or

correlation of dependent variables

2002-01-31 Thread John Smith
If I have 3 variables defined as follows: A, B as independent, uncorrelated values of 0 or 1 C defined as the logical AND of AB, such that C=1 if and only if both A B =1, and 0 otherwise. Example A=1, B=0 then C=0 A=0, B=1 then C=0 A=0, B=1 then C=0 A=1, B=1 then C=1 My question is, what is

Re: correlation of dependent variables

2002-01-31 Thread Dennis Roberts
+ ** - - * - --+-+-+-+-+-+C16 304050607080 MTB corr c16 c17 Pearson correlation of C16 and C17 = -0.005 P-Value = 0.959 then i did the sum

Re: correlation of dependent variables

2002-01-31 Thread Vadim Pliner
The answer is E(CA)=EA*EB. This is why: You have C=A*B. Therefore, E(CA)=E((A**2)*B))=E(A*B)=EA*EB. The second to last equality holds because A**2=A, and the last one is correct because A and B are independent. Vadim [EMAIL PROTECTED] (John Smith) wrote: If I have 3 variables defined as

Re: Testing Correlation in Joint PDF

2002-01-22 Thread Chia C Chong
m of 2-D joint PDF f(X,Y)=f(Y|X)f(X).I would like to test the correlation between them to see whether there are correlated or not. Do I simply find the correlation coeffient between these two variables or are there other ways that I could use to test correlation?? If you're interested in ass

Re: Testing Correlation in Joint PDF

2002-01-22 Thread Chia C Chong
their correlation between them by simply use the Pearson correlation coefficent, r formulae. However, r values was so small (i.e. r=0.08). This means that X Y are not linearly dependent, which is expected from the conditinoal and marginal PDFs that I have derived. So, does this mean in my case finding r value

Testing Correlation in Joint PDF

2002-01-20 Thread Chia C Chong
Hi! I have 2 random varaibles (X and Y) obtained from some experiments. I have expressed these 2 RVs in ternm of 2-D joint PDF f(X,Y)=f(Y|X)f(X).I would like to test the correlation between them to see whether there are correlated or not. Do I simply find the correlation coeffient between

Re: Correlation problem

2002-01-07 Thread Stephen Clark
janne [EMAIL PROTECTED] wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... I have a correlation formula I don't get to work. And we must use this formula on the test. Let me give you an example: Let's say X and Y are: xy 1 68 2 91 3 102 3 107 4 105 4

Re: Correlation problem

2002-01-07 Thread Art Kendall
the sum of the crossproducts. Stephen Clark wrote: janne [EMAIL PROTECTED] wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... I have a correlation formula I don't get to work. And we must use this formula on the test. Let me give you an example: Let's say X and Y are: x

Re: Correlation problem

2002-01-07 Thread Elliot Cramer
In sci.stat.consult janne [EMAIL PROTECTED] wrote: : I have a correlation formula I don't get to work. And we must use this : formula on the test. Let me give you an example: Let's say X and Y If you don't know with x(with a line above) MEANS, you need to STUDY your text. Also your instructor

Re: Correlation problem

2002-01-07 Thread Dennis Roberts
sum of deviations around a mean always = 0 X-X 1-3.5=2.5 2-3.5=-1.5 3-3.5=-0.5 3-3.5=-0.5 4-3.5=0.5 4-3.5=0.5 5-3.5=1.5 6-3.5=2.5 0 As you see the answer is zero. What do I do wrong? and the same with Y-Y(with a line above). It turns out to be zero. Please help me to tell how I

Re: Correlation problem

2002-01-07 Thread Timothy E. Vaughan
janne [EMAIL PROTECTED] wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... How do I do the first (X-X(with a line above))? I have tried to take _ X-X *snip* 0 As you see the answer is zero. What do I do wrong? You calculate SUM[(x-x_bar)] * SUM[(y-y_bar)] instead

Correlation problem

2002-01-06 Thread janne
I have a correlation formula I don't get to work. And we must use this formula on the test. Let me give you an example: Let's say X and Y are: xy 1 68 2 91 3 102 3 107 4 105 4 114 5 115 6 127 _ ___ 28 829 __ X is =3.5 and Y is =103.625 Now to my

Correlation problem

2002-01-06 Thread janne
I have a correlation formula I don't get to work. And we must use this formula on the test. Let me give you an example: Let's say X and Y are: xy 1 68 2 91 3 102 3 107 4 105 4 114 5 115 6 127 _ ___ 28 829 __ X is =3.5 and Y is =103.625 Now to my

Re: Correlation problem

2002-01-06 Thread Bill Rowe
In article [EMAIL PROTECTED], janne [EMAIL PROTECTED] wrote: I have a correlation formula I don't get to work. And we must use this formula on the test. Let me give you an example: Let's say X and Y are: [example omitted] As you see the answer is zero. What do I do wrong? Nothing. For any

Nonparametric, Correlation Data Analysis

2002-01-01 Thread TimOneil05
Hello, I'm doing a project that requires me to utilize the both Spearman and Pearson correlation formulas. Does anyone know a good software program that will let me do so? I have tried using Winks but it does not do the job too well. Any and all help is greatly appreciated. Thank you in advance

Re: Who said Correlation does not imply causation.

2001-12-11 Thread EugeneGall
Andrew Morse wrote: Who was the first to say Correlation does not imply causation in so many words? I know that the idea dates back to David Hume, but Hume did his work about a century before the term correlation acquired its modern statitical meaning. It certainly wasn't Hume, who's argument

Re: Who said Correlation does not imply causation.

2001-12-11 Thread Herman Rubin
In article [EMAIL PROTECTED], EugeneGall [EMAIL PROTECTED] wrote: Andrew Morse wrote: Who was the first to say Correlation does not imply causation in so many words? I know that the idea dates back to David Hume, but Hume did his work about a century before the term correlation acquired its

Re: Who said Correlation does not imply causation.

2001-12-09 Thread EugeneGall
Andrew Morse wrote: Who was the first to say Correlation does not imply causation in so many words? I know that the idea dates back to David Hume, but Hume did his work about a century before the term correlation acquired its modern statitical meaning. It certainly wasn't Hume, who's argument

RE: When does correlation imply causation?

2001-12-07 Thread jim clark
Hi On 6 Dec 2001, David Heiser wrote: Most of the focus is on structural equation modeling (SEM). For statisticians, a quick referral to Jim Steiger's article Driving Fast in Reverse in JASA March 2001, p331-p338 (if you have it around) is a quick discourse on SEM and the inherent problems

Re: When does correlation imply causation?

2001-12-07 Thread Jay Warner
. Jay [EMAIL PROTECTED] wrote: Classic study: Correlation between local stork population and local births. -Original Message- From: Stu [mailto:[EMAIL PROTECTED]] Sent: Thursday, December 06, 2001 1:08 AM To: [EMAIL PROTECTED] Subject: Re: When does correlation imply causation? My

Re: When does correlation imply causation?

2001-12-06 Thread Alex Yu
Whether we can get causal inferences out of correlation and equations has been a dispute between two camps: For causation: Clark Glymour (Philosopher), Pearl (Computer scientist), James Woodward (Philosopher) Against: Nancy Cartwright (Economist and philosopher), David Freedman

Re: When does correlation imply causation?

2001-12-06 Thread Art Kendall
the value of some form of correlation coefficient? I certainly agree with that. - - - The observation that a correlation exists is one point in an inductive argument about causation. The entire argument shows causation. If we cannot show some form of correlation an important element of a casual

Experimental Correlation Coefficients

2001-12-06 Thread Wuensch, Karl L
statistic). Does correlation (phi is not equal to zero) imply causation in this case? That is, can I conclude that turning the lights on affects my ability to read fine print? I modify my experiment such that Y is now the reading on an instrument that measure the intensity of light

RE: When does correlation imply causation?

2001-12-06 Thread hdaley
Classic study: Correlation between local stork population and local births. -Original Message- From: Stu [mailto:[EMAIL PROTECTED]] Sent: Thursday, December 06, 2001 1:08 AM To: [EMAIL PROTECTED] Subject: Re: When does correlation imply causation? My favorite original example

Re: Experimental Correlation Coefficients

2001-12-06 Thread Dennis Roberts
computed with dichotomous data). Phi = .5. I test and reject the null hypothesis that phi is zero in the population (using chi-square as the test statistic). Does correlation (phi is not equal to zero) imply causation in this case? That is, can I conclude that turning the lights on affects my ability

Re: Who said Correlation does not imply causation.

2001-12-05 Thread Juha Puranen
Stu wrote: Silvert, Henry wrote: Might I go one step further and point out the correlation does not establish a causal relationship primarily because it does not point to directionality, at least not without a working hypothesis and some background support. Absolutely. Without both

Re: When does correlation imply causation?

2001-12-05 Thread Mike Granaas
On Wed, 5 Dec 2001, Karl L. Wuensch wrote: much stuff snipped So why is it that many persons believe that one can make causal inferences with confidence from the results of two-group t tests and ANOVA but not with the results of correlation/regression techniques. I believe

Re: When does correlation imply causation?

2001-12-05 Thread Dennis Roberts
correlation NEVER implies causation ... and i agree with mike totally At 09:01 AM 12/5/01 -0600, Mike Granaas wrote: We really need to emphasize over and over that it is the manner in which you collect the data and not the statistical technique that allows one to make causal inferences

Re: When does correlation imply causation?

2001-12-05 Thread Dennis Roberts
At 07:36 AM 12/5/01 -0500, Karl L. Wuensch wrote: Accordingly, I argue that correlation is a necessary but not a sufficient condition to make causal inferences with reasonable confidence. Also necessary is an appropriate method of data collection. To make such causal

RE: When does correlation imply causation?

2001-12-05 Thread Wuensch, Karl L
Dennis warns the problem with this is ... does higher correlation mean MORE cause? lower r mean LESS cause? in what sense can think of cause being more or less? you HAVE to think that way IF you want to use the r value AS an INDEX MEASURE of cause ... Dennis is not going to like this, since he

Correlation :: causation

2001-12-05 Thread Art Kendall
. If correlation (in the broad sense) remains after taking into account (controlling, rendering unlikely) plausible rival hypotheses, it does imply (support, suggest, indicate, make plausible) causation. In experimental studies, active manipulation of independent variables, and random assignment to conditions

RE: When does correlation imply causation?

2001-12-05 Thread Dennis Roberts
Correlations: dosage, res1 Pearson correlation of dosage and res1 = 1.000 P-Value = * but, for another set of data we get MTB plot c3 c1 Plot res2- * - - 1.00

RE: When does correlation imply causation?

2001-12-05 Thread Dennis Roberts
... and observe the same result we want to say that the impact to the FACE ... CAUSED the person on the left to fall down but, did it? in a sense, this is like a perfect correlation in that ... when the person swung to the RIGHT .. the person on the left NEVER fell backwards and down with an r = 1, karl

Re: When does correlation imply causation?

2001-12-05 Thread Rich Ulrich
On 5 Dec 2001 08:52:41 -0800, [EMAIL PROTECTED] (Dennis Roberts) wrote: correlation NEVER implies causation ... That is true - in the strong sense, and - in formal logic, and - as a famous quotation among researchers. (And, reported as wrongly contrasted to 'ANOVA'.) Or, correlation always

Re: When does correlation imply causation?

2001-12-05 Thread Stan Brown
Dennis Roberts [EMAIL PROTECTED] wrote in sci.stat.edu: personally, i think it is dangerous in ANY case to say that r = cause ... Hear, hear! My favorite original example is the correlation between number of annual murders in a city and number of books in its libraries. Students have

Re: When does correlation imply causation?

2001-12-05 Thread Stu
My favorite original example is the correlation between number of annual murders in a city and number of books in its libraries. Students have no trouble seeing that the two are going to have a fairly high correlation coefficient(*), but murders don't make people read and books don't make

RE: Who said Correlation does not imply causation.

2001-12-04 Thread Silvert, Henry
Might I go one step further and point out the correlation does not establish a causal relationship primarily because it does not point to directionality, at least not without a working hypothesis and some background support. Henry M. Silvert Ph.D. Research Statistician The Conference Board 845

Re: Who said Correlation does not imply causation.

2001-12-04 Thread jim clark
Hi On 3 Dec 2001, Karl L. Wuensch wrote: I think that phrase has created much misunderstanding. I try to convince my students that correlation is necessary but not sufficient for establishing a causal relationship. And I teach that NEITHER presence NOR absence of _simple_ correlation can

Re: Who said Correlation does not imply causation.

2001-12-04 Thread Karl L. Wuensch
Nice example. Perhaps I should have said partial (and not necessarily linear) correlation. - Original Message - From: jim clark [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Tuesday, December 04, 2001 1:37 PM Subject: Re: Who said Correlation does not imply causation. Hi On 3 Dec

Re: Who said Correlation does not imply causation.

2001-12-04 Thread Glen
[EMAIL PROTECTED] (Andrew Morse) wrote in message news:[EMAIL PROTECTED]... Who was the first to say Correlation does not imply causation in so many words? I know that the idea dates back to David Hume, but Hume did his work about a century before the term correlation acquired its modern

Re: Who said Correlation does not imply causation.

2001-12-04 Thread David Duffy
Andrew Morse [EMAIL PROTECTED] wrote: Who was the first to say Correlation does not imply causation in so many Kendall and Stuart says ...Yule (1926) frightened statisticians by adducing cases of very high correlations which were obviously not causal..., in time-series data, as it happens

Who said Correlation does not imply causation.

2001-12-04 Thread Stu
---BeginMessage--- Silvert, Henry wrote: Might I go one step further and point out the correlation does not establish a causal relationship primarily because it does not point to directionality, at least not without a working hypothesis and some background support. Absolutely. Without

Re: Who said Correlation does not imply causation.

2001-12-03 Thread Karl L. Wuensch
I think that phrase has created much misunderstanding. I try to convince my students that correlation is necessary but not sufficient for establishing a causal relationship. Karl L. Wuensch, Department of Psychology,East Carolina University, Greenville NC 27858-4353Voice: 252-328-4102

Re: Who said Correlation does not imply causation.

2001-12-02 Thread Art Kendall
I don't recall who coined that phrase. However, it is frequently misused. Sometimes it is used to put down bad researchers who use correlational methods (including ordinary regression) and good researchers who use ANOVA methods. Sometimes it is used to mean that if there is correlation

Re: Who said Correlation does not imply causation.

2001-12-02 Thread Art Kendall
I don't recall who coined that phrase. However, it is frequently misused. Sometimes it is used to put down bad researchers who use correlational methods (including ordinary regression) and good researchers who use ANOVA methods. Sometimes it is used to mean that if there is correlation

Re: Who said Correlation does not imply causation.

2001-12-02 Thread Art Kendall
I don't recall who coined that phrase. However, it is frequently misused. Sometimes it is used to put down bad researchers who use correlational methods (including ordinary regression) and good researchers who use ANOVA methods. Sometimes it is used to mean that if there is correlation

Who said Correlation does not imply causation.

2001-12-01 Thread Andrew Morse
Who was the first to say Correlation does not imply causation in so many words? I know that the idea dates back to David Hume, but Hume did his work about a century before the term correlation acquired its modern statitical meaning. I've seen many sources that crdit Karl Pearson with banishing

How to verify significance of coefficient of correlation when distributive law is indeterminate (unknown)

2001-11-27 Thread Yuri Krushinsky
*** post for FREE via your newsreader at post.newsfeeds.com *** subj? I find books only with a case of regular distributive law Any references to online resources are welcome -= Posted via Newsfeeds.Com, Uncensored Usenet News =- http://www.newsfeeds.com - The #1 Newsgroup Service in

Re: canonical correlation question

2001-08-17 Thread Elliot Cramer
Gardburyb [EMAIL PROTECTED] wrote: : Hi all, : I'm new to the group. I'm doing my dissertation, and I am doing a canonical : correlation analysis. My question is, what is the best way to compare canonical The test of parallelism in mancova is an equivalent test

Re: canonical correlation question

2001-08-17 Thread Paige Miller
Elliot Cramer wrote: Gardburyb [EMAIL PROTECTED] wrote: : Hi all, : I'm new to the group. I'm doing my dissertation, and I am doing a canonical : correlation analysis. My question is, what is the best way to compare canonical The test of parallelism in mancova is an equivalent test

Re: canonical correlation question

2001-08-17 Thread Rich Ulrich
this is, in reference to what test (what computer program, or what textbook)? I'd like to ask a follow-up question then. MANCOVA uses least squares as its objective function to estimate relationships, while canonical correlation uses a different objective function. They don't seem equivalent

Re: Interclass Correlation??

2001-07-30 Thread Rich Ulrich
are in a particular order, or if that is randomized - between patients, or within a patient. Is the balance test pass-fail, or does it produce a score on some scale (as 'correlation' implies)? Is there a 'Gold Standard' for performance? Does a performance, after going 'beyond' learning, post

RE: Interclass Correlation??

2001-07-24 Thread Paul R. Swank
Dickin Sent: Monday, July 23, 2001 10:08 PM To: [EMAIL PROTECTED] Subject: Interclass Correlation?? I am trying to determine the reliability of a balance test for individuals with Alzheimer's disease. The test involves six different conditions, with each condition consisting of three trials (6 x 3

Interclass Correlation??

2001-07-23 Thread Clark Dickin
I am trying to determine the reliability of a balance test for individuals with Alzheimer's disease. The test involves six different conditions, with each condition consisting of three trials (6 x 3). Each individual has performed the complete test twice, which gives me 6 trials for each of the 6

Confidence interval for Pearson Correlation

2001-07-20 Thread Alexandre Moura
Dear Members, How can I construct a confidence interval about Pearson correlation using standard error and t value? What is the formula? Regards, Alexandre Moura. = Instructions for joining and leaving this list and remarks

Re: Confidence interval for Pearson Correlation

2001-07-20 Thread Dennis Roberts
construct a confidence interval about Pearson correlation using standard error and t value? What is the formula? Regards, Alexandre Moura. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE

Re: 3rd degree polynom curve fitting, correlation needed

2001-06-18 Thread Paige Miller
Matti Overmark wrote: I have fitted a 3 rd degree curve to a sample (least square method), and I want to compare this particular R2 with that of a (similarily) fitted 2 degree polynom. I can assure you that the 3rd degree polynomial will fit as well or better than the 2nd degree polynomial,

3rd degree polynom curve fitting, correlation needed

2001-06-18 Thread Matti Overmark
Hi group! I´m new to this group, so...just you know. I have fitted a 3 rd degree curve to a sample (least square method), and I want to compare this particular R2 with that of a (similarily) fitted 2 degree polynom. I want to see which of the two models is the best. Any suggestion of a good

Re: 3rd degree polynom curve fitting, correlation needed

2001-06-18 Thread Mike Granaas
Judd McClelland, _Data Analysis: A Model Comparison Approch_, chapter 8. MG On 18 Jun 2001, Matti Overmark wrote: Hi group! I´m new to this group, so...just you know. I have fitted a 3 rd degree curve to a sample (least square method), and I want to compare this particular R2 with

Re: Correlation of complex data

2001-04-16 Thread Peter J. Wahle
the square terms, or all the product terms? What is the 1_2 inner product? How should the complex result be interpreted--what exactly is the meaning? | Can the linear correlation coefficient equation (Pearson's) be used for | calculating the correlation coefficient of complex variables

Re: Correlation of vectors

2001-04-11 Thread Jos Jansen
If it makes sense to represent your data as 4 column vectors, say y1 and y2 for the first set and x1 and x2 for the second, then you may consider to calculate the canonical correlation between (y1,y2) and (x1,x2). Jos Jansen "Peter J. Wahle" [EMAIL PROTECTED] wrote in message WcQA6.

Re: Correlation of vectors

2001-04-10 Thread W. D. Allen Sr.
for independence and need some sort of measure of correlation. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =

Re: Correlation of vectors

2001-04-10 Thread Peter J. Wahle
The cross product is another vector. Two vectors are orthogonal if their dot product is zero. This is not what I'm looking for. I have two sets of 2-D vectors that I need to determine their correlation or dependence. If I remember correctly two vectors are independent if their cross product

algorithm cross correlation

2001-02-15 Thread Hanke
Does anyone know a algorithm for cross-correlation between two time series to identify leading and lagging indicators and the size of the lag? Do you know a algorithm in C or f77. SAS adn SPSS just calculate this and quickly do it for each lag and lead, but i need a algorithm for own

dataset for weight/height correlation

2001-02-02 Thread Dale Glaser
Hi there.a colleague needs a recent estimate of height/weight correlation of adults (age 18 or over)..I've searched the various major websites (CDC, etc.), and one huge dataset had weight/height but not according to the specs my colleague needed..any datasets that you can recommend

Re: Cross-correlation of two random signals gives bimodal distribution

2000-11-01 Thread Robert J. MacG. Dawson
I don't knwo Matlab, but: I create two random signals (each 100 points from gaussian distribution from -1 to 1) You mean 100 IID Gaussian-distributed points, indexed by values from -1 to 1? (I'm assuming this, anyway.) and find the maximum cross-correlation value (either

Re: Cross-correlation of two random signals gives bimodal distribution

2000-10-31 Thread Rich Ulrich
On Mon, 30 Oct 2000 18:54:12 -0800, "G. Anthony Reina" [EMAIL PROTECTED] wrote: I'm having a problem concerning cross-correlation and was hoping someone could help explain. Here's what I'm doing: I create two random signals (each 100 points from gaussian distribution fr

Cross-correlation of two random signals gives bimodal distribution

2000-10-30 Thread G. Anthony Reina
I'm having a problem concerning cross-correlation and was hoping someone could help explain. Here's what I'm doing: I create two random signals (each 100 points from gaussian distribution from -1 to 1) and find the maximum cross-correlation value (either negative or positive, whichever has

correlation/regression and causation

2000-10-21 Thread Karl L. Wuensch
use of them):1) It demonstrates that a correlation problem in which one variable is dichotomous is equivalent to a two-group mean-difference problem." You all may find this hard to believe, but, in my experience, a large proportion of social scientists have the delusion that if you conduct a tra

Re: correlation/regression and causation

2000-10-21 Thread dennis roberts
in the continuous variable is caused by alteration of the dichotomous variable), but if you analyze the same variables with a correlation analysis you cannot make a causal inference. I show my students and colleagues the equivalence of testing the null that the point biserial is zero and testing

Statistical- or correlation- or .... analysis of data ?

2000-08-13 Thread AJ
, fn_different(t). I'm interested in preforming some sort of correlation/statistical analysis of the data, that can tell me how the part of the data in fn(t), that are varying (ie. fn_different(t)) are dependent of eachother, ie. are the parts statically independent, or not and if not with which distribution do

Re: Statistical- or correlation- or .... analysis of data ?

2000-08-13 Thread Donald Burrill
h varyhing fn(t)? Or is that part of what is to be inferred from the data? I'm interested in performing some sort of correlation/statistical analysis of the data, that can tell me how the part of the data in fn(t), that are varying (ie. fn_different(t)) are dependent of each other, ie. are

Re: polyserial correlation in prelis 2

2000-08-09 Thread jsuebersax
I think I understand your question better now than in my first reply: In article [EMAIL PROTECTED], castlemaster [EMAIL PROTECTED] wrote: there is a test of model with chi-sq value, d.f. and p-value provided for the polyserial correlation coefficients in prelis 2. is it a test of close fit

polyserial correlation in prelis 2

2000-08-06 Thread castlemaster
hi, there is a test of model with chi-sq value, d.f. and p-value provided for the polyserial correlation coefficients in prelis 2. is it a test of close fit or a test of significance? does a test of significance exist? any reference? many thanks

Re: bivariate normality and correlation

2000-07-13 Thread Znarf Akfak
In article [EMAIL PROTECTED] (Donald Burrill) wrote: Sounds like a prediction or calibration kind of problem. As Joe Ward pointed out, raw regression coefficients, and standard errors of measurement, are more stable than correlation coefficients. Yes, that's right. Regression

Re: bivariate normality and correlation

2000-07-12 Thread Donald Burrill
t, readers will. We want to report the correlation between two methods of measurement for about 20-30 different response variables. It isn't expected that the methods will give the same individual or average values, but the degree of linear correlation is useful in future large studi

Re: bivariate normality and correlation

2000-07-11 Thread Znarf Akfak
; and even if you don't, readers will. We want to report the correlation between two methods of measurement for about 20-30 different response variables. It isn't expected that the methods will give the same individual or average values, but the degree of linear correlation is useful in future lar

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