Dear all, I would like to perform a receiver operating characteristics (ROC) curve analysis on data obtained using molecular assays. I have here an example: the first column is the sample number, the second is the response variable and the last three columns are the predictors. I wish to set the formula to test as R ~ P1 + P2 + P3 in order to obtain the cut-offs for each of the predictors combined. Any tip on how to proceed? Thank you Best regards, Luigi R P1 P2 P3 1 0 0.725196908 0 0 2 0 1.089876198 0 0 3 0 1.487365838 0 0 4 0 6.214688703 3.625 0 5 0 48.26356415 13.4 0 6 1 9.494694175 0 0 7 1 15.57700003 4.666 0 8 1 45.53510205 15.57 0 9 1 0.373389928 12.55 1 10 1 0.692909116 0 1 11 1 15.05400384 3.45 1 12 1 20.83909961 6.9 1 13 1 23.24171357 0 1 14 1 43.51470584 0 1 15 1 49.80855616 3.55 1 16 1 664.0886249 10.37 1 17 2 60.85094536 3.725 0 18 2 62.7104185 0 1 19 2 143.7426283 6.5 1
On Tue, Oct 23, 2012 at 11:52 PM, Luigi <marongiu.luigi at gmail.com> wrote:> > Any tip on how to proceed?You may want to do check rocplus package. Its vignette is pretty good. http://cran.r-project.org/web/packages/rocplus/vignettes/rocplus.pdf In your case, I think pairwise comparison would be one approach Best, Mehmet