question 3 Find the critical value zc necessary to form a confidence interval at the level of confidence shown below.

c=0.93

zc=

(Round to two decimal places asneeded.)

question 4 Find the margin of error for the given values ofc, , and n.

c=0.90, =3.4, n=81

E=

(Round to three decimal places asneeded.)

question 6 Use the confidence interval to find the margin of error and the sample mean.

(0.598,0.760)

The margin of error is

question 7 Find the minimum sample size n needed to estimate for the given values ofc, , and E.

c=0.98, =9.3, and E=2

Assume that a preliminary sample has at least 30 members.

n=

(Round up to the nearest wholenumber.)

question 8 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 55 home theater systems has a mean price of $143.00. Assume the population standard deviation is $15.40.

Construct a90% confidence interval for the population mean.

The90% confidence interval is ( ____,_____)

(Round to two decimal places asneeded.)