91Ó°ÊÓ

The Focus Problem at the beginning of the chapter indicates that attendance at large exhibition shows in Denver averages about 8000 people per day, with standard deviation of about 500 . Assume that the daily attendance figures follow a normal distribution. (a) What is the probability that the daily attendance will be fewer than 7200 people? (b) What is the probability that the daily attendance will be more than 8900 people? (c) What is the probability that the daily attendance will be between 7200 and 8900 people?

Let \(z\) be a random variable with a standard normal distribution. Find the indicated probability, and shade the corresponding area under the standard normal curve. $$ P(z \geq-1.50) $$