failure mode and rate analysis

Instead of the ordinal ranking of frequency, 1 to 5, used in problem 10.1, the director of quality improvement has collected data on the number of each type of surgery and the number of patients that contracted a postoperative infection. The director wants you to recalculate the RPN using the actual incidence rate of infection. Infection severity and detectability are ranked the same as in problem 10.1. How does the use of incidence rate change the improvement worklist? Which surgery should be examined last? What is the maximum possible risk score for this analysis?