You are given the sample mean and the population standard deviation. Use this information to construct the90% and95% confidence intervals for the population mean. Interpret the results and compare the widths of the confidence intervals. Ifconvenient, use technology to construct the confidence intervals.

A random sample of 45 home theater systems has a mean price of $121.00. Assume the population standard deviation is $17.80.

Construct a90% confidence interval for the population mean.

The90% confidence interval is (

nothing

,

nothing

).

(Round to two decimal places asneeded.)

Construct a95% confidence interval for the population mean.

The95% confidence interval is (

nothing

,

nothing

).

(Round to two decimal places asneeded.)

Interpret the results. Choose the correct answer below.

A.

With90% confidence, it can be said that the population mean price lies in the first interval. With95% confidence, it can be said that the population mean price lies in the second interval. The95% confidence interval is wider than the90%.

B.

With90% confidence, it can be said that the population mean price lies in the first interval. With95% confidence, it can be said that the population mean price lies in the second interval. The95% confidence interval is narrower than the90%.

C.

With90% confidence, it can be said that the sample mean price lies in the first interval. With95% confidence, it can be said that the sample mean price lies in the second interval. The95% confidence interval is wider than the90%.