22. According to the Bureau of Labor Statistics, the average weekly pay for a U.S. production worker was $441.84 (The World Almanac, 2000). Assume that available data indicate that production worker wages were normally distributed with a standard deviation of $90.

a. What is the probability that a worker earned between $400 and $500 per week?

b. How much did a production worker have to earn per week to be in the top 20% of wage earners?

c. For a randomly selected production worker, what is the probability the worker earned less than $250 per week?