1. Find the critical value z_c necessary to form a confidence interval at the level of confidence shown below. c=0.92

2. Find the margin of error for the given values of c, σ, and n.

c = 0.95, σ =2.4, n = 8.1

Level of Confidence. zc

90% 1.645

95% 1.96

99% 2.575

3. Construct the confidence interval for the population mean μ.

c=0.98, x=9.5, σ=0.3, and n= 52

4. Construct the confidence interval for the population mean μ.
   c=0.95, x=16.7, σ=6.0, and n= 95
5. Find the minimum sample size n needed to estimate μ for the given values of c, σ, and E.

c=0.95, σ=5.7, and E=2. Assume that a preliminary sample has at least 30 members.

6. Find the minimum sample size n needed to estimate μ for the given values of c, σ, and E.

c=0.95, σ=5.6, and E=2. Assume that a preliminary sample has at least 30 members.

7. You are given the sample mean and the population standard deviation. Use this information to construct the 90% and 95% confidence intervals for the population mean. Interpret the results and compare the widths of the confidence intervals. If convenient, use technology to construct the confidence intervals. A random sample of 45 home theater systems has a mean price of $131.00. Assume the population standard deviation is $19.90. Construct a 90% confidence interval for the population mean.
8. From a random sample of 49 dates, the mean record high daily temperature in a certain city has a mean of 83.08°F. Assume the population standard deviation is 14.61°F.This creates a 95% confidence interval for the population mean of (78.99, 87.17). Does it seem possible that the population mean could be greater than 91°F? Explain.
9. Determine the minimum sample size required when you want to be 90% confident that the sample mean is within one unit of the population mean and σ=13.8. Assume the population is normally distributed. A 90% confidence level requires a sample size of nothing.