Normal Distribution Problem. Porphyrin is a pigment in blood protoplasm and other body fluids that is significant in body energy and storage. Assume porphyrin is normally distributed with mean (mu) = 38 milligrams per deciliter and standard deviation (sigma) = 11 milligrams per deciliter. What is the probability that x is greater than 60? Please use 4 decimal places and use the proper rules of rounding. Excel can be a helpful calculator in these problems, especially the Normal Excel 2020.xlsx file..