Recall the Empirical Rule from Chapter 3. It states that if the data distribution is bell-shaped, then the interval m { s contains approximately 68% of the values, m { 2s contains approximately 95%, and m { 3s contains virtually all of the data values. The bell-shaped distribution referenced is the normal distribution.

a. Verify that a standard normal distribution contains approximately 68% of the values in the interval m { s.

b. Verify that a standard normal distribution contains approximately 95% of the values in the interval m { 2s.

c. Verify that a standard normal distribution contains virtually all of the data in the interval m { 3s.