Plot Positive and Negative Predictive Values for Medical Tests //
Functions to plot and help understand positive and negative
predictive values (PPV and NPV), and their relationship with
sensitivity, specificity, and prevalence. See Akobeng, A.K.
(2007) doi:10.1111/j.1651-2227.2006.00180.x for a theoretical
overview of the technical concepts and Navarrete et al. (2015)
for a practical explanation about the importance of their
understanding doi:10.3389/fpsyg.2015.01327.