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Re: nomogram
Posted:
Jul 12, 2006 9:43 AM


No, we do not "always use beta = 0.1.
Question:
Are you doing this work stirctly around the matter of testing whether there is a "real difference" between two averages? Something that would eventually lead to a Student ttest? If so, there's a simple equation for estimating the proper sample size for a particular choice of alpha and beta. OMU
Natalie Vivien wrote: > Hi everyone! > > I am assigned a school project to design a clinical trial. I was told > to calculate power. I remember power is the probability of rejecting Ho > when Ho is false which is 1beta. Do we always use beta=0.1? I read > this up in a statistical book. > > If so, how do we use the nomogram to look for the corresponding sample > size? The chart is the one which has two scales by the sides (one for > difference and one for power) and a straight line in the middle with a > decreasing gradient (indicating the sample size)? > > Hope someone can help me if not I will be stuck in the initial stage. :)



