The average cholesterol content of a certain brand of eggs is 215 milligrams, and the standard deviation is 15 milligrams. Assume the variable is normally distributed.
a. If a single egg is selected, find the probability that the cholesterol content will be greater than 220 milligrams.
b. If a sample of 25 eggs is selected, find the probability that the mean of the sample will be larger than 220 milligrams.