# Question: The standard deviation for a population is 14 8

The standard deviation for a population is σ = 14.8. A sample of 25 observations selected from this population gave a mean equal to 143.72. The population is known to have a normal distribution.

a. Make a 99% confidence interval for µ.

b. Construct a 95% confidence interval for µ.

c. Determine a 90% confidence interval for µ.

d. Does the width of the confidence intervals constructed in parts a through c decrease as the confidence level decreases? Explain your answer.

a. Make a 99% confidence interval for µ.

b. Construct a 95% confidence interval for µ.

c. Determine a 90% confidence interval for µ.

d. Does the width of the confidence intervals constructed in parts a through c decrease as the confidence level decreases? Explain your answer.

## Relevant Questions

The standard deviation for a population is σ = 6.30. A random sample selected from this population gave a mean equal to 81.90. The population is known to be normally distributed. a. Make a 99% confidence interval for µ ...Explain the meaning of a point estimate and an interval estimate. Lazurus Steel Corporation produces iron rods that are supposed to be 36 inches long. The machine that makes these rods does not produce each rod exactly 36 inches long. The lengths of the rods vary slightly. It is known that ...You are interested in estimating the mean commuting time from home to school for all commuter students at your school. Briefly explain the procedure you will follow to conduct this study. Collect the required data from a ...For each of the following, find the area in the appropriate tail of the t distribution. a. t = 2.467 and df = 28 b. t = –1.672 and df = 58 c. t = –2.670 and n = 55 d. t = 2.819 and n = 23Post your question