1. Use the Empirical Rule (page 454) to answer the following questions. A standardized test of intelligence is scaled so that the mean IQ is 100, and the standard deviation is 15.

1. What percent of people have an IQ between 85 and 115?

1. What percent of people have an IQ greater than 115?

1. What percent of people have an IQ less than 130?

1. What percent of people have an IQ less than 70?

1. Use Z-scores to solve the following question.

In math class, Samantha scored 10 on a quiz for which the class mean was 7.6 and the class standard deviation was 2.1. Marie scored 8.5 on a quiz for which the class mean was 5.9 and the class standard deviation was 2.1. Relatively speaking, who had the better score? What was each of their z-scores? (See page 458)

1. Using technology or the table on page 418, find the following probabilities. Tell what method you used.

1. Between -1.10 and 0.47

1. To the left of 1.05

1. To the right of 2.38

Extra credit

A fruit-packing company produced peaches last summer whose weights were normally distributed with a mean 14 ounces and standard deviation 0.6 ounces. Among a sample of 1000 of those peaches, about how many could be expected to have weights as follows?

1. At least 14 ounces

1. Between 14 and 15.2 ounces

1. Less than 13.4 ounces

1. More than 12 ounces

1. Between 13.5 and 15.5 ounces