Normally distributed observations such as a person's weight, height or shoe size occur quite frequently in nature. Business people who are aware of this use it to their advantage. A purchasing agent for a college bookstore buying 300 golf shirts used the normal curve to decide on the order quantities for the various sizes. If men's average shirt size is 15.5 with a standard deviation of.50, how many shirts should be ordered in sizes over 16.5?
A) 7
B) 8
C) 9
D) 10
E) 6

Question

Quizplus · Accepted Answer

The z-score for a shirt size of 16.5 is (16.5 - 15.5) / 0.50 = 2.0. The area to the right of this z-score is 0.0228, which means that about 2.28% of men have shirt sizes over 16.5. Therefore, the purchasing agent should order about 300 * 0.0228 = 6.84 shirts in sizes over 16.5. Since the purchasing agent cannot order a fraction of a shirt, he should order 7 shirts in sizes over 16.5.

Normally Distributed Observations Such as a Person's Weight, Height or Shoe