Chapter 8 Homework: Problem 16 Previous Problem Problem List Next Problem (1 poi

Question

Chapter 8 Homework: Problem 16 Previous Problem Problem List Next Problem (1 point) Among the most exciting aspects of a university professor's life are the departmental meetings where such critical issues as the color the walls will be painted and who gets a new desk are decided. A sample of 20 professors was asked how many hours per year are devoted to such meetings. The responses are listed below. Assuming that the variable is normally distributed with a standard deviation of 7 hours, estimate the mean number of hours spent at departmental m eetings by all professors. Use a confidence level of 90%. 7, 10, 16, 2, 19, 5, 20, 13, 16, 17, 13, 9,7, 12, 15, 3, 13, 17, 4, 16 Note: For each confidence interval, enter your answer in the form (LCL, UCL). You must include the parentheses and the comma between the confidence limits. You should use technology to help you with this problem (Minitab :)). Give your answers to at least 2 decimal places Confidence Interval =

Explanation / Answer

Performing Manually -

The sample mean of the data is 11.7

Standard error of the sampling distriution of mean = Standard deviation / sqrt(Sample Size)

= 7 / sqrt(20) = 1.57

Z value at 90% confidence interval is 1.64

Margin of error = Z value * Standard error = 1.64 * 1.57 = 2.57

90% confidence interval is (11.7 - 2.57, 11.7 + 2.57)

= (9.13, 14.27)

Performing in minitab -

Follow below steps to get the same results in minitab.

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