1. The purchasing department of the RCMP must order uniform hats for new recruits. Past experience tells the Purchasing Manager that the circumferences of officers' heads are approximately normally distributed with mean 22.8 inches and standard deviation 1.1 inches.

What proportion of officers has big heads (i.e., exceeding 24.5 inches in circumference)?

2. Suppose midterm exam scores in a math course are normally distributed with a mean of 60 and a standard deviation of 20. What is the interquartile range? (Hint: Start by finding Q1 and Q3 for a standard normal distribution.)