Em Qua, 2008-10-08 às 17:41 -0700, Halizah Basiron escreveu: > Hi all, > I am newbie in using R software and also doing statistical test. I want to > know if my data in in normal distribution. I have 2 groups of data and I did > calculate Shapiro Wilks using R software. Here is the results: > > Group 1: W = 0.9206, p-value = 0.01683 > Group 2: W = 0.9626, p-value = 0.4694 > > I am not quite sure what default confidence level (CF) is used in calculating > Shapiro Wilks. Else, may I choose my own CF. Let say, if I choose CF = 0.01, > therefore I may approve that Group 1 and Group 2 data are normal. If not, > what should I do. My next plan is to apply T Test for both groups (assuming > both are normal). I really need advice from experts here. > > Cheers, > Halizah
Hi Halizah, In my opinion don't exist confidence level of test. What exist is confidence level of your experiment. If you plan your experiment with alpha probability you have 100*(1-alpha) confidence level and you p-value need minor than alpha to named "significant" So if you need 99% of significance the two groups is normal and you using t.test. -- Bernardo Rangel Tura, M.D,MPH,Ph.D National Institute of Cardiology Brazil ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
