*The next three problems refer to the following:* According to a Field Poll, 79% of California adults (actual results are 400 out of 506 surveyed) feel that “education and our schools” is one of the top issues facing California. We wish to construct a 90% confidence interval for the true proportion of California adults who feel that education and the schools is one of the top issues facing California. (Source: http://field.com/fieldpollonline/subscribers/)

### Exercise 24

A point estimate for the true population proportion is:

**A.**0.90**B.**1.27**C.**0.79**D.**400

#### Solution

C

### Exercise 25

A 90% confidence interval for the population proportion is:

**A.**(0.761, 0.820)**B.**(0.125, 0.188)**C.**(0.755, 0.826)**D.**(0.130, 0.183)

#### Solution

A

### Exercise 26

The error bound is approximately

**A.**1.581**B.**0.791**C.**0.059**D.**0.030

#### Solution

D

*The next two problems refer to the following:*

A quality control specialist for a restaurant chain takes a random sample of size 12 to check the amount of soda served in the 16 oz. serving size. The sample mean is 13.30 with a sample standard deviation of 1.55. Assume the underlying population is normally distributed.

### Exercise 27

Find the 95% Confidence Interval for the true population mean for the amount of soda served.

**A.**(12.42, 14.18)**B.**(12.32, 14.29)**C.**(12.50, 14.10)**D.**Impossible to determine

#### Solution

B

### Exercise 28

What is the error bound?

**A.**0.87**B.**1.98**C.**0.99**D.**1.74

#### Solution

C

### Exercise 29

What is meant by the term “90% confident” when constructing a confidence interval for a mean?

**A.**If we took repeated samples, approximately 90% of the samples would produce the same confidence interval.**B.**If we took repeated samples, approximately 90% of the confidence intervals calculated from those samples would contain the sample mean.**C.**If we took repeated samples, approximately 90% of the confidence intervals calculated from those samples would contain the true value of the population mean.**D.**If we took repeated samples, the sample mean would equal the population mean in approximately 90% of the samples.

#### Solution

C

*The next two problems refer to the following:*

Five hundred and eleven (511) homes in a certain southern California community are randomly surveyed to determine if they meet minimal earthquake preparedness recommendations. One hundred seventy-three (173) of the homes surveyed met the minimum recommendations for earthquake preparedness and 338 did not.

### Exercise 30

Find the Confidence Interval at the 90% Confidence Level for the true population proportion of southern California community homes meeting at least the minimum recommendations for earthquake preparedness.

**A.**(0.2975, 0.3796)**B.**(0.6270, 6959)**C.**(0.3041, 0.3730)**D.**(0.6204, 0.7025)

#### Solution

C

### Exercise 31

The point estimate for the population proportion of homes that do not meet the minimum recommendations for earthquake preparedness is:

**A.**0.6614**B.**0.3386**C.**173**D.**338

#### Solution

A

Comments:"Part of the Books featured on Community College Open Textbook Project"