I tried to plot ROC curve using pROC packages, the code is as following:
install.packages("pROC")
require("pROC")
pMDmedian <- roc(MDmeanall$IDH.type, MDmeanall$MD_median, plot=TRUE, print.thres=TRUE, print.auc=TRUE)
The scale of the specificity is defaulted as from 1.5 to -0.5, while what I wish is the scale from 0.0 to 1. The sensitivity also has similar problem.