Hi, I am running a simple one-way ANOVA with an independent factot variable "treat" (3 levels: a, b and c) and a response variable "y". I want to test a linear relationship of the response among the 3 levels of the variable "treat" (ordered a->b->c). I used glht() from multcomp package. Later I found out I need to exclude the situation where the response at the 3 levels of "treat" are equal. I can do separate contrasts to test them separately:
obj<-aov(y~treat,data=dat) ### testing a=b=c summary(glht(obj, linfct= mcp (treat=c('a-b=0','a-c=0','b-c=0'))),test=Ftest()) ### testing linear relationship among a,b and c summary(glht(obj, linfct= mcp (treat=c('a+c-2*b=0'))),test=Ftest()) Is there anyway to build one contrast that tests both at the same time, i.e. just generate one single p value. Because the ultimate purpose was to test the linear relationship among the 3 levels of the variable "treat". Or I am asking something that is non-sensible to do? Thanks John Zhang ____________________________________________________________________________________ Looking for last minute shopping deals? ______________________________________________ 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.