Hi, I have a question about what CV should be entered in CV or PairCVs option in Pairmeans of Power Procedure for lognormal data. See the SAS documentation for CV below. CV=number-list specifies the coefficient of variation that is assumed to be common to both members of a pair. The coefficient of variation is defined as the ratio of the standard deviation to the mean on the original data scale. You can use this option only with DIST=LOGNORMAL. For information about specifying the number-list, see the section Specifying Value Lists in Analysis Statements. This sounds like, when data are assumed lognormally distributed, CVs entered should be STD/mean, and STD and Mean are calculated from data in the original scale. However, in SAS/STAT® 13.1 User’s Guide The POWER Procedure, Page 6445-6446 If CV=SD/Mean, where SD and Mean are calculated from data in original scale, how the σ* (SD from log-transformed data) can be derived from sqrt(log(CV2+1))? Instead, if CV is calculated from CV=sqrt(exp(SDlog2)-1) where SDlog is the SD from natural Log scale data, then it makes sense that σ* (SDlog) can be derived by back-calculating. However, the documentation clearly indicates the inputted CV is from data in original scale. This confuses me. Also have a similar question about the correlation, as the documentation states to enter "correlation of the original untransformed pairs (Y1; Y2)". Thanks,
... View more