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Topic: Validity of correlation coefficient for binary data
Replies: 1   Last Post: Oct 24, 1996 11:31 AM

 Joe H Ward Posts: 743 Registered: 12/6/04
Re: Validity of correlation coefficient for binary data
Posted: Oct 24, 1996 11:31 AM

Hi Ronan, Drake, and others who may be interested in STATISTICAL HISTORY
or those who have to take a STATISTICAL HISTORY TEST!

Below is a summary of some of the names given to a few indicators of
relationships.

-- Joe
***********************************************************************
* Joe Ward 167 East Arrowhead Dr. *
* Health Careers High School San Antonio, TX 78228-2402 *
* Phone: 210-433-6575 *
* joeward@tenet.edu *
***********************************************************************

SUMMARY OF SOME "INDICATORS OF RELATIONSHIP"
FROM CHAPTER 9 OF
GLASS AND STANLEY -"STATISTICAL METHODS IN EDUCATION AND PSYCHOLOGY"
(PRENTICE-HALL, 1970)

| MEASUREMENT OF VARIABLE X
__________________|___________________________________________________________
| | |
MEASUREMENT OF | | Dichotomous, with | Interval
VARIABLE Y | Dichotomous | underlying normal | or Ratio
__________________|________________|______________________|___________________
| | |
Dichotomous | phi | |
__________________|________________|______________________|___________________
| | |
Dichotomous, with | | tetrachoric |
underlying normal | | r(tet) |
__________________|________________|______________________|___________________
| | |
Interval or | point- | biserial | Pearson
Ratio | biserial | | product-moment
| r(pb) | r(bis) | r(xy)
__________________|________________|______________________|___________________

On Thu, 24 Oct 1996, Ronan M Conroy wrote:

> Date: Thu, 24 Oct 1996 05:01:57 -0400
> From: Ronan M Conroy <rconroy@rcsi.ie>
> To: Multiple recipients of list <edstat-l@jse.stat.ncsu.edu>
> Subject: Re: Validity of correlation coefficient for binary data
>
> At 3:07 pm 23/10/96, Drake R. Bradley wrote:

> >Actually, I think the correlation between two binary variables would be
> >a phi coefficient. The correlation between a binary (dichotomous) variable
> >and a "true" quantitative variavle (non-binary) is a point biserial
> >correlation. The formulae for r-phi and r-pb are just simplifications of
> >the standard Pearson product-moment r.
> >
> > The phi coefficient is tested using the chi-square test (2x2),[snip]

>
> in fact, phi squared is chi squared divided by N. Although I have known
> about phi since my youth, I have never once fired it in anger, or even
> pointed it at anyone in fun. Does anyone out there use it?
>
> _/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
>
> _/_/_/ _/_/ _/_/_/ _/ Ronan M Conroy
> _/ _/ _/ _/ _/ _/ Lecturer in Biostatistics
> _/_/_/ _/ _/_/_/ _/ Royal College of Surgeons
> _/ _/ _/ _/ _/ Dublin 2, Ireland
> _/ _/ _/_/ _/_/_/ _/ +353 1 402 2431 fax 402 2329
>
> _/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
> Why does no-one whistle anymore?
>
>
>