Hi all, I have a data of lognormal distribution (sample size > 1,000,000). What I want to do is 1) to test if my dataset is a lognormal distribution or not (Histogram shows a nice normal distribution in log scale but I want to check) 2) two subsets from this dataset have same mean or not (like "t test" of normal distribution) What I tried are 1) ad.test{truncgof} of R, which is a "Supremum Class Anderson-Darling test" but I got error message. What I had problems are 1) Memory error happen with error message of "cannot allocate vector of size 1.0GB" and I cannot increase the computer spec. 2) I don't know what is "t test" of lognormal. What I am thinking is 1) Is it OK to convert the data in log scale and do perform t test to say these dataset has same mean? How can I solve my problem? Thank you for any comments. Hyunchul [[alternative HTML version deleted]]