118.

Suppose that the insurance companies did do a survey. They randomly surveyed 400 drivers and found that 320 claimed they always buckle up. We are interested in the population proportion of drivers who claim they always buckle up.

1. 1. x = __________
   2. n = __________
   3. p = __________
2. Define the random variables X and P, in words.
3. Which distribution should you use for this problem? Explain your choice.
4. Construct a 95% confidence interval for the population proportion who claim they always buckle up.
   1. State the confidence interval.
   2. Sketch the graph.
   3. Calculate the error bound.
5. If this survey were done by telephone, list three difficulties the companies might have in obtaining random results.

119.

According to a recent survey of 1,200 people, 61% feel that the president is doing an acceptable job. We are interested in the population proportion of people who feel the president is doing an acceptable job.

1. Define the random variables X and P in words.
2. Which distribution should you use for this problem? Explain your choice.
3. Construct a 90% confidence interval for the population proportion of people who feel the president is doing an acceptable job.
   1. State the confidence interval.
   2. Sketch the graph.
   3. Calculate the error bound

Use the following information to answer the next three exercises: 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.

125.

A point estimate for the true population proportion is:

1. 0.90
2. 1.27
3. 0.79
4. 400

126.

A 90% confidence interval for the population proportion is _______.

1. (0.761, 0.820)
2. (0.125, 0.188)
3. (0.755, 0.826)
4. (0.130, 0.183)