Hi there, I tried to use the function ancova to analyze covariance in my model. my model is like the following; I want to include two treatments(trt1, trt2) , their interaction and one covariate (covar1) y ~ trt1+trt2+trt1*trt2+ covar1 R code: mydata$trt1=factor(mydata$trt1) # 2 levels contrasts(mydata$trt1)=contr.treatment(2) mydata$trt2=factor(mydata$trt2) # 2 levels contrasts(mydata$trt2)=contr.treatment(2) mydata$trt1.trt2=interaction(mydata$trt1,mydata$trt2) contrasts(mydata$trt1.trt2) <- contr.treatment(4) model=ancova(y ~ trt1*trt2+ covar1, data=mydata) # there is no error message model1=ancova(y ~ trt1+trt1*trt2+covar1, data=mydata) there is error message *Error in ancova(DELTA_PANSS ~ drug + drug.SULT + BASE, data = mydata_drug) : ancova requires exactly one factor and exactly one numeric variable. * model2=ancova(y ~ trt1+trt2+trt1*trt2+covar1, data=mydata) *Error in .subset2(x, i, exact = exact) : recursive indexing failed at level 2 In addition: Warning message: In formula.plot[[3]][2:3] <- formula[[3]][2 + classes] : number of items to replace is not a multiple of replacement length * It will be really helpful if you could point out my mistake or point me to the right model and function I should use. Thank you, Qian [[alternative HTML version deleted]]

Hi there, I tried to use the function ancova to analyze covariance in my model. my model is like the following; I want to include two treatments(trt1, trt2) , their interaction and one covariate (covar1) y ~ trt1+trt2+trt1*trt2+ covar1 R code: mydata$trt1=factor(mydata$trt1) # 2 levels contrasts(mydata$trt1)=contr.treatment(2) mydata$trt2=factor(mydata$trt2) # 2 levels contrasts(mydata$trt2)=contr.treatment(2) mydata$trt1.trt2=interaction(mydata$trt1,mydata$trt2) contrasts(mydata$trt1.trt2) <- contr.treatment(4) model=ancova(y ~ trt1*trt2+ covar1, data=mydata) # there is no error message model1=ancova(y ~ trt1+trt1*trt2+covar1, data=mydata) there is error message *Error in ancova(DELTA_PANSS ~ drug + drug.SULT + BASE, data = mydata_drug) : ancova requires exactly one factor and exactly one numeric variable. * model2=ancova(y ~ trt1+trt2+trt1*trt2+covar1, data=mydata) *Error in .subset2(x, i, exact = exact) : recursive indexing failed at level 2 In addition: Warning message: In formula.plot[[3]][2:3] <- formula[[3]][2 + classes] : number of items to replace is not a multiple of replacement length * It will be really helpful if you could point out my mistake or point me to the right model and function I should use. Thank you, Qian [[alternative HTML version deleted]]

Hi Qian, Sorry but the HH package is a CRAN package, not a Bioconductor package. You might want to ask on the R-help mailing list or contact its maintainer directly. Don't forget to provide your sessionInfo(). Cheers, H. On 03/15/2011 09:21 AM, Qian Liu wrote: > Hi there, > > I tried to use the function ancova to analyze covariance in my model. > my model is like the following; I want to include two treatments(trt1, trt2) > , their interaction and one covariate (covar1) > y ~ trt1+trt2+trt1*trt2+ covar1 > > R code: > mydata$trt1=factor(mydata$trt1) # 2 levels > contrasts(mydata$trt1)=contr.treatment(2) > mydata$trt2=factor(mydata$trt2) # 2 levels > contrasts(mydata$trt2)=contr.treatment(2) > mydata$trt1.trt2=interaction(mydata$trt1,mydata$trt2) > contrasts(mydata$trt1.trt2)<- contr.treatment(4) > > model=ancova(y ~ trt1*trt2+ covar1, data=mydata) # there is no error > message > > model1=ancova(y ~ trt1+trt1*trt2+covar1, data=mydata) there is error message > > *Error in ancova(DELTA_PANSS ~ drug + drug.SULT + BASE, data = mydata_drug) > : > ancova requires exactly one factor and exactly one numeric variable. > * > model2=ancova(y ~ trt1+trt2+trt1*trt2+covar1, data=mydata) > > *Error in .subset2(x, i, exact = exact) : > recursive indexing failed at level 2 > In addition: Warning message: > In formula.plot[[3]][2:3]<- formula[[3]][2 + classes] : > number of items to replace is not a multiple of replacement length > * > It will be really helpful if you could point out my mistake or point me to > the right model and function I should use. > Thank you, > Qian > > [[alternative HTML version deleted]] > > _______________________________________________ > Bioconductor mailing list > Bioconductor at r-project.org > https://stat.ethz.ch/mailman/listinfo/bioconductor > Search the archives: http://news.gmane.org/gmane.science.biology.informatics.conductor > -- Hervé Pagès Program in Computational Biology Division of Public Health Sciences Fred Hutchinson Cancer Research Center 1100 Fairview Ave. N, M2-B876 P.O. Box 19024 Seattle, WA 98109-1024 E-mail: hpages at fhcrc.org Phone: (206) 667-5791 Fax: (206) 667-1319