Question

# You are given the sample mean and the population standard deviation. Use this information to construct...

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 40 home theater systems has a mean price of ​\$140.00 Assume the population standard deviation is ​\$19.50.

The 90% confidence interval is?

The 95% confidence interval is?

n= 40, = 140, = 19.50

We are using TI-83 calculator as folllows,

a)

c= 90 %

134.93 < < 145.07

The​ 90% confidence interval is ( 134.93 , 145.07)

b)

c= 95 %

133.96 < < 146.04

The​ 95% confidence interval is ( 133.96 , 146.04)

c)

With​ 90% confidence, it can be said that the population mean price lies in the first interval. With​ 95% confidence, it can be said that the population mean price lies in the second interval. The​ 95% confidence interval is wider than the​ 90%.

#### Earn Coins

Coins can be redeemed for fabulous gifts.