A random sample of the closing stock prices in dollars for a company in a recent year is listed below. Assume that

sigma

is

$2.34

Construct the

90%

and

99%

confidence intervals for the population mean. Interpret the results and compare the widths of the confidence intervals.

22.17	22.37	20.25	19.33	15.97	22.29	15.81	20.01
17.56	19.01	19.31	17.08	16.25	22.23	18.54	15.88

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Part 1

The 90% confidence interval is left parenthesis $ nothing comma $ nothing right parenthesis .$enter your response here,$enter your response here.

(Round to two decimal places as needed.)

Part 2

The 99% confidence interval is left parenthesis $ nothing comma $ nothing right parenthesis .$enter your response here,$enter your response here.

(Round to two decimal places as needed.)

Part 3

Which statement below interprets the results correctly?

The 90% confidence interval contains the mean closing stock price 90% of the time and the 99% confidence interval contains the mean closing stock price 99% of the time.

The probability that the mean closing stock price is in the 90% confidence interval is about 90% and the probability that the mean closing stock price is in the 99% confidence interval is about 99%.

90% of the mean closing stock prices are in the 90% confidence interval and 99% of the mean closing stock prices are in the 99% confidence interval.

There is 90% confidence that the mean closing stock price is in the 90% confidence interval and 99% confidence that the mean closing stock price is in the 99% confidence interval.

Part 4

Which interval is wider?

The 90% confidence interval

The 99% confidence interval