The assignment file has already been updated, so if you haven't downloaded it yet, stop reading.
Original:
7-13(d)."Do the points on the PSI ROC curve represent approximate quintiles of predicted risk? How can you tell?"
New:
"Do the points on the PSI calibration plot represent approximate quintiles of risk? In other words, does each category of predicted risk contain roughly one-fifth of the population? How can you tell? (Hint: Looking at the ROC curve may help.)"