I must calculate the sample size for a paired t-test. Data used in the test are log transformed. The difference between the log transformed data is 2 log and the SD is 1 log. To calculate the sample size, do I use the formula of lognormal distribution with a mean ratio of 10**2 and a SD of 10**1 or do I use the formula of normal distribution with a mean difference of 2 and a SD of 1?
Thank you for your help.