makeAugmentedSample: Create randomized residuals and observations for data sets that have some censored data
Description
This function is used to add two columns to the Sample data frame: rResid and rObserved.
rResid is the randomized residual value computed in log concentration units, and rObserved
is the randomized 'observed' value of concentration in concentration units.
Both of these are computed for all censored samples ("less than values").