The distribution of results from a cholesterol test has a mean of 180 and a standard deviation of 20. A sample size of 40 is drawn randomly.

a.Find the probability that the sum of the 40 values is greater than 7,500.

b. Find the sum that is one standard deviation above the mean of the sums.

c. Find the percentage of sums between 1.5 standard deviations below the mean of the sums and one standard deviation above the mean of the sums