At 04:28 AM 1/16/2003, Michael Specka wrote:
On 15 Jan 2003 07:09:49 -0800, [EMAIL PROTECTED] (Dennis Roberts) wrote:

>just as an example ... say you had a null hypothesis that the population
>correlation was 0 ... (this is typical for the null) and ... you had a
>sample size of about 1000 ... it would only take an r of about .06 ... for
>you to reject the null ... however, do you think that accounting for .06^2
>... = ..0036 or less than 1% of the criterion variance ... is enough such
>that you would be willing to use X (which might be data that is costly to
>collect) as a predictor of Y?

Agreed. But there might be circumstances where even small
correlations provide important information and justify certain
actions. If the 0.06 correlation comes from a death rate of
250 out of 500 in one treatment and 220 out of 500 in the other
treatment...
agreed ... small effects CAN be important ... and, one could argue that any treatment that saves even just one life (over an old method) is "worth it" ... but, if that treatment cost is $4,000,000 ... society might judge otherwise

effects of treatments have to factor in cost (to society/tax payers/citizens, etc.) too


Regards

Michael
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_________________________________________________________
dennis roberts, educational psychology, penn state university
208 cedar, AC 8148632401, mailto:[EMAIL PROTECTED]
http://roberts.ed.psu.edu/users/droberts/drober~1.htm
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