Why do you want to test for normality and equal variances? If those are really a concern then you should use a method up front that is robust against those. Those tests are usually testing a hypothesis that is different from what you are actually interested in and generally have low power to guide further tests.
-- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare greg.s...@imail.org 801.408.8111 > -----Original Message----- > From: r-devel-boun...@r-project.org [mailto:r-devel-bounces@r- > project.org] On Behalf Of Karthi Subramanian > Sent: Monday, January 24, 2011 10:06 AM > To: R-devel@r-project.org > Subject: [Rd] normality and equal variance testing > > I currently have a program that automates 2-way ANOVA on a series of > endpoints, > but before the ANOVA is carried out I want the code to test the > assumptions of > normality and equal variance and report along with each anova result in > the > output file. How can I do this? > > > I have pasted below the code that I currently use. > > > library(car) > numFiles = x # <--<--<--<--<--<--<--<--<--<--<-- supply the number of > files > containing the source data here > for (iIndx in 1:numFiles) { > sinkFilePath = paste("C:/AnovaData/2WayAnovaForProteins_Set", > iIndx, > ".txt", sep="") > sink(sinkFilePath) > sourceFilePath = paste("C:/AnovaData/ProteinsFor2WayAnova_Set", iIndx, > ".txt", > sep="") > dataSet = read.delim(sourceFilePath) > numProteins = ncol(dataSet) > nameProteins = colnames(dataSet) > for (i in 3:numProteins) { > fla = as.formula(paste(nameProteins[i],"~","Trt*Dose")) > mod = lm(fla, data = dataSet , contrasts = list(Trt = contr.sum, Dose > = > contr.sum)) > ano = Anova(mod, type = "III") > print.noquote("") > print.noquote("") > print.noquote("--------------------------------------------") > print.noquote(paste("--------- Analysis of Spot: > ",nameProteins[i],"------------")) > print.noquote("--------------------------------------------") > print(ano) > } > } > > > Thanks in advance. > Karthi > > > [[alternative HTML version deleted]] ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
