#1 Construct the indicated confidence interval for the population mean using the t-distribution. Assume the population is normally distributed.

c=0.90, x=13.6, s=2.0, n=5

(Round to one decimal place as needed.)

#2 Construct the indicated confidence interval for the population mean using the t-distribution. Assume the population is normally distributed.

c=0.90, x=12.3, s=0.74, n=17

(Round to one decimal place as needed.)

#3 In a random sample of 18 people, the mean commute time to work was 32.6 minutes and the standard deviation was 7.1 minutes. Assume the population is normally distributed and use a t distribution to construct a 80% confidence interval for the population mean .

What is the margin of error of ? Interpret the results.

#4 The state test scores for 12 randomly selected high school seniors are shown on the right. Complete parts (a) through (c) below. Assume the population is normally distributed.

1427 1220 981 700 725 837 720 744 540 624 1445 941

(a) Find the sample mean.

(b )Find the sample standard deviation.

(c) Construct a 99% confidence interval for the population mean .

#5 Use the standard normal distribution or the t-distribution to construct a 99% confidence interval for the population mean. Justify your decision. If neither distribution can be used, explain why. Interpret the results.In a random sample of 19 mortgage institutions, the mean interest rate was 3.42% and the standard deviation was 0.35%.

Assume the interest rates are normally distributed.