Solve the problem.

A newspaper article about the results of a poll states: “In theory, the results of such a poll, in 99 cases out of 100 should differ by no more than 5 percentage points in either direction from what would have been obtained by interviewing all voters in the United States.” Find the sample size suggested by this statement. (Points : 5)

544

664

27

385

**Question**

Use the confidence level and sample data to find a confidence interval for estimating the population mu. Round your answer to the same number of decimal places as the sample mean.

Test scores: n = 92, mean = 90.6, sigma = 8.9; 99% confidence (Points : 5)

88.4 < mu < 92.8

88.8 < mu < 92.4

88.2 < mu < 93.0

89.1 < mu < 92.1

**Question**

Use the given information to find the minimum sample size required to estimate an unknown population mean mu.

Margin of error: $120, confidence level: 95%, sigma = $593 (Points : 5)

133

94

83

66

**Question**

Assume that a sample is used to estimate a population mean mu. Use the given confidence level and sample data to find the margin of error. Assume that the sample is a simple random sample and the population has a normal distribution. Round your answer to one more decimal place than the sample standard deviation.

95% confidence; n = 91; x-bar = 16, s = 9.1 (Points : 5)

1.71

4.10

1.63

1.90

**Question**

Use the given degree of confidence and sample data to construct a confidence interval for the population mean mu. Assume that the population has a normal distribution.

A laboratory tested twelve chicken eggs and found that the mean amount of cholesterol was 225 milligrams with s = 15.7 milligrams. Construct a 95% confidence interval for the true mean cholesterol content of all such eggs. (Points : 5)

215.0 mg < mu < 235.0 mg

216.9 mg < mu < 233.1 mg

214.9 mg < mu < 235.1 mg

215.1 mg < mu < 234.9 mg