My name is Thalita, and I am a Phd student from Brasil. I am trying to do a post hoc of ANCOVA to compare three slopes with Tukey test. I am using: #percentagem: dependent variable #tratamento: factor #tempo: covariate #ANCOVA ancova(percentagem~tratamento*tempo, data=data) summary(ancova(percentagem~tratamento*tempo, data=data)) mod<-ancova(percentagem~tratamento*tempo,data=data) glht(mod, linfct=mcp(tratamento="Tukey")) summary(glht(mod, linfct=mcp(tratamento="Tukey"))) ## but I think that # compare just the intercep So, I would like to know how can compare the three slopes. I saw this page in internet (https://stat.ethz.ch/pipermail/r-help/2012-February/303327.html), but I did't understood how to compare. Thankk you Kind Regards -- *Thalita Gabriella ZimmermannBi?loga, MSc.* *Doutoranda em Bot?nica * *Laborat?rio de Sementes - DIPEQInstituto de Pesquisas Jardim Bot?nico do Rio de Janeiro* [[alternative HTML version deleted]]