Hi, maybe your data are distributed according a log-normal distribution, so logs are normally distributed. But remerber the significancy of t test can applied only on log transformated data and not on original data. See basic hypothesis for t testing, in alternative use non-parametric methods to compare results. Best Vito
You wrote: Hello, I got two sets of data x=(124738, 128233, 85901, 33806, ...) y=(25292, 21877, 45498, 63973, ....) When I did a t test, I got two tail p-value = 0.117, which is not significantly different. If I changed x, y to log scale, and re-do the t test, I got two tail p-value = 0.042, which is significantly different. Now I got confused which one is correct. Any help would be very appreciated. Thanks, Liu ===== Diventare costruttori di soluzioni Visitate il portale http://www.modugno.it/ e in particolare la sezione su Palese http://www.modugno.it/archivio/cat_palese.shtml ___________________________________ http://it.seriea.fantasysports.yahoo.com/ ______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
