The distribution of retirement age for NFL players is normally distributed with a mean of 33 years old and a standard deviation of about 2 years. Suppose we sample 20 players. a. What is the sampling distribution of the sample mean of 20 players? b. What is the probability that the average age of retirement, x, of a sample of 20 players is above 35 years? What average age of retirement, x, of 20 players that is the 95th percentile? C.