being statistically significant is highly influenced by n
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?
At 06:04 AM 1/15/03 -0800, Lizzy wrote:
With a very large sample size (n=15000), what is the validity of secondary outcomes if sample size calculations were based on the primary outcome only(death)and the primary outcome itself does not show differences between treatment arms?One to four out of 13 secondary outcomes/ outcome subgroups showed significant difference between treatment arms. Can one state that these data are valid, "hard" data, taking into account the very large sample size? No adjustments for cut off point for p-values where done. This regards the clinical interpretation of data from one large drug trial. Thank you for responding, regards, Lizzy . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
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