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# An experiment involves selecting a random sample of 256 middle managers. We would like to know the mean salary (annual income).

An experiment involves selecting a random sample of 256 middle managers. We would like to know the mean salary (annual income). The sample mean salary is 45,000, and the sample standard deviation is \$2,000. Calculate the 95% confidence interval, showing the confidence limits. Hint, because the sample size is greater than 30, we use the Z factor for 95%. INCLUDE AN EXCEL SPREADSHEET SHOWING YOUR WORK TO CALCULATE THE 95% CONFIDENCE INTERVAL. You can use Excel functions, or show your work manually using the Confidence Interval formula shown on page 306 of the Doane & Seward text. (Formula 8.6). You better look in the text, it does not paste well here. And the text also provides the Z factor for this 95% problem.

Test1: 60, 60, 60, 60, 71, 73, 74, 75, 88, 99
Test 2: 65, 65, 65, 65, 70, 74, 79, 79, 79, 79
Test 3: 66, 67, 70, 71, 72, 72, 74, 74, 95, 99
Test 4: 10, 49, 70, 80, 85, 88, 90, 93, 97, 98 test 1...

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