<[EMAIL PROTECTED]> wrote in message 8mbhrh$fuk$[EMAIL PROTECTED]">news:8mbhrh$fuk$[EMAIL PROTECTED]...
> Hello from Germany,
> as a part of my dissertation in medicine, I have
> to summarize some results of clinical trials.
> My question: By summarizing the results
> (percentage differences of certain parameters),
> how can I regard for the different p-values
> (which are calculated with different tests in the
> trials). Is it possible to form something like a
> weighet mean with the p-values and the sample
> sizes in the trials to generate an common effect
> size of the different results in the trials?
>
> Thanks for your comments,
> Marc
There exist ways of combining p-values from independent
tests. However, they don't generally weight by n, because
that's already taken into account in the p-value. (e.g. Fisher's
technique of summing -2log p_i and comparing with a chi-
squared distribution with df equal to twice the number of tests.)
It sounds, however, like you're attempting a meta-analysis,
which other people would be more qualified than I am to
explain the various pitfalls and problems of.
Glen
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