search for: levenetest

Dear all, For my research I need to perform a Levene's test on my data.I have not large experience with this test and with R,so I have some problems to use the leveneTest function. I read some previous posts on this topic but I cannot understand what I have to do. I have a five-columns data frame organised in the following way: number of observation, number of subject, score, type of treatment (I have 4 of them), number of replication (3 replications). My idea was...

...+ x12 + x13 + x14 + x15 + x16 + x17 + x18 + F1+ F2+ F3, data = dds, weights = erro.y, na.action = na.exclude) For this model, I haven't normal distribution on residuals and they aren't homoscedastic. So I tried a boxcox transformation: residuo<-residuals(mod) lillie.test(residuo) leveneTest(residuo~F1,data=dds) leveneTest(residuo~F2,data=dds) leveneTest(residuo~F3,data=dds) boxcox(model) modnew<-lm((y^1.3-1)/1.3 ~ x1 + x2 + x3 + x4 + x5 + x6 + x7 + x8 + x9 + x10 + x11 + x12 + x13 + x14 + x15 + x16 + x17 + x18 + F1+ F2+ F3, data = dds, weights = erro.y, na.action = na.exclude)...

...zero occur, could anyone help me to fix this problem? asim <- 1000 pv<-rep(NA,asim) for(i in 1:asim) {print(i) set.seed(i) g1 <- rnorm(20,0,2) g2 <- rnorm(20,0,2) g3 <- rnorm(20,0,2) x <- c(g1,g2,g3) group<-as.factor(c(rep(1,20),rep(2,20),rep(3,20))) library(Rcmdr) pv[i]<-leveneTest(x,group)$p.value } -- View this message in context: http://r.789695.n4.nabble.com/simulation-of-levene-s-test-tp4631578.html Sent from the R help mailing list archive at Nabble.com.

I am trying to use Levene's test (of package car), but I do not understand quite well how to use it. '?levene.test' does not unfortunately provide any example. My data are in a data frame and correspond to 1 factor plus response. Could someone please give me an example about how to use the command levene.test(y, group) Thanks in advance, marta -- View this message in

Dear Mariano, See the function leveneTest() in the car package. I hope that this helps, John ----------------------------- John Fox, Professor Emeritus McMaster University Hamilton, Ontario, Canada Web: socialsciences.mcmaster.ca/jfox/ > -----Original Message----- > From: R-help [mailto:r-help-bounces at r-project.org] On Behal...