In Melanie's Styling Salon, the time to complete a simple haircut is normally distributed with a mean of 30 minutes and a standard deviation of 8 minutes. What percent of customers require less than 16 minutes?

a. 0.0401

b. 0.5401

c. 0.4599

d. 0.9599

You arrive at a bus stop, with no bus standing, and you want to model how long you'll need to wait for the next bus. The sign says that busses arrive about every 30 minutes, so you assume the arrival is equally likely to be anywhere between 0 and 30 minutes. What is the probability that the bus would arrive within the next 24 minutes?

a. 0.57

b. 0.43

c. 0.2

d. 0.8

Because some passengers who make flight reservations do not showup to claim their reservations, airlines often overbook flights. A certain flight has capacity of seating 160 passengers. The airline believes that the rate of passenger"no-show" is 4% and has made reservations for 163 passengers for this flight. Let random variable X be the number of "no-show"s for this flight. Then the standard deviation of X is:

a. 6.145

b. 6.26

c. 2.479

d. 2.502