Suppose that scores on a statistics final were normally distributed with a mean of 75 points and a standard deviation of 8 points.Find the following:

a.The probability that a randomly selected student form the class will score more than 80 points on the final.

b.The 40thpercentile of the scores.

c.The minimum score needed to score in the top 10%.

d.Suppose that a sample of 30 students who took the final is selected.Find the probability that their mean score is less than 70.