1. Construct the indicated confidence interval for the population mean

using the t-distribution. Assume the population is normally distributed.

c=0.90,

x=14.2,

s=2.0,

n=6

2. In a random sample of

19 people, the mean commute time to work was

33.3 minutes and the standard deviation was

7.2 minutes. Assume the population is normally distributed and use a t-distribution to construct a

95% confidence interval for the population mean .

What is the margin of error of ?

The confidence interval for the population mean is _________

(Round to one decimal place as needed.)

The margin of error of is __________

3. In a random sample of

8

people, the mean commute time to work was

33.5

minutes and the standard deviation was

7.3

minutes. A

98%

confidence interval using the t-distribution was calculated to be

(25.8,41.2).

After researching commute times to work, it was found that the population standard deviation is

8.8

minutes. Find the margin of error and construct a

98%

confidence interval using the standard normal distribution with the appropriate calculations for a standard deviation that is known. Compare the results.

The margin of error of is _______

(Round to two decimal places as needed.)

A 98% confidence interval using the standard normal distribution is __________

(Round to one decimal place as needed.)