Hello, I am looking for a sample size function for samples sizes, to test
proportions that are not binomial proportions. The proportions represent a
ratio of (final measure) / (baseline measure) on the same experimental unit.
Searches using RSeek and such bring multiple hits for binomial proportions, but
that doesn't seem to fit my situation. Perhaps there's some standard
terminology from a different field that would provide better hits than deeming
this a 'rate' or a 'proportion'.
Of course, most sample size functions assume a normal distribution, while this
data will be bounded between 0 and 1. The scientist I'm working with feels
it's important to make fair comparisons, any weight loss must account for the
baseline weight. A logistic transformation seems appropriate, but that term
also didn't yield hits I recognized as useful.
Loss of weight --- compare treatments:
Treatment A: 1 - Final weight / Initial weight
Treatment B: 1 - Final weight / Initial weight
This appears to be a situation that would be common, but I'm not framing it in
a way that matches an R package. Any guidance is appreciated.
Regards, Paul
Paul Prew ⪠Statistician
651-795-5942 ⪠fax 651-204-7504
Ecolab Research Center ⪠Mail Stop ESC-F4412-A
655 Lone Oak Drive ⪠Eagan, MN 55121-1560
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