lesDistr The lesion distribution matrix, an [1:nRow,2] array, where
nRow is the number of unique values of lesions per case
in the dataset. The first column contains the number of lesions.
The second column contains the fraction of diseased cases with the number
of lesions indicated in the first column. See
PlotRsmOperatingCharacteristics for a function that depends on
lesDistr. See Chapter00Vignette2 for more details.