In Melanie's Styling Salon, the time to complete a simple haircut is normally distributed with a mean of 25 minutes and a standard deviation of 4 minutes. What percent of customers require greater than 26.6 minutes?

a. 0.1554

b. 0.3446

c. 0.6554

d. 0.8446

A large number of applicants for admission to graduate studies in business are given an aptitude test with a resulting mean score of 400 and a standard deviation of 70. The scores are known to follow a normal distribution. The top 2.5 percent of the applicants would have a score of at least (choose the nearest integer)

a. 592

b. 512

c. 444

d. 537

A certain famous Canadian tennis player makes a successful first serve 50% of the time. Assume that each serve is independent of the others. If she serves 6 times, what is the probability that not all of these first serves are in?

a. 0.9844

b. 0.9844

c. 0.0156

d. 0.0156