13.A manager is interested in improving productivity at a plant by changing the layout of the workstation. For each of 10 workers, she measures the time it takes to complete a task before the change and after the change. She calculates the following summary statistics for the sample difference: mean sample difference (between before and after) = 8.5 and sample standard deviation of the difference = 11.38. Assuming that the difference in time taken to complete the task is normally distributed, what is the critical value used to determine whether the mean difference (in task completion time) between before and after the change is not equal to zero at the 5% level of significance? Use our textbook statistical table to answer the question. a.±2.2281 b.±2.1009 c.±2.2622 d.±1.96

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Answered: A manager is interested in improving…

Essentials of Business Analytics (MindTap Course List)

2nd Edition

ISBN:9781305627734

Author:Jeffrey D. Camm, James J. Cochran, Michael J. Fry, Jeffrey W. Ohlmann, David R. Anderson

Publisher:Jeffrey D. Camm, James J. Cochran, Michael J. Fry, Jeffrey W. Ohlmann, David R. Anderson

Chapter7: Linear Regression

Section: Chapter Questions

Problem 2P: In a manufacturing process the assembly line speed (feet per minute) was thought to affect the...

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13.

A manager is interested in improving productivity at a plant by changing the layout of the workstation. For each of 10 workers, she measures the time it takes to complete a task before the change and after the change. She calculates the following summary statistics for the sample difference: mean sample difference (between before and after) = 8.5 and sample standard deviation of the difference = 11.38. Assuming that the difference in time taken to complete the task is normally distributed, what is the critical value used to determine whether the mean difference (in task completion time) between before and after the change is not equal to zero at the 5% level of significance? Use our textbook statistical table to answer the question.

a.
±2.2281

b.
±2.1009

c.
±2.2622

d.
±1.96

Features Features Normal distribution is characterized by two parameters, mean (µ) and standard deviation (σ). When graphed, the mean represents the center of the bell curve and the graph is perfectly symmetric about the center. The mean, median, and mode are all equal for a normal distribution. The standard deviation measures the data's spread from the center. The higher the standard deviation, the more the data is spread out and the flatter the bell curve looks. Variance is another commonly used measure of the spread of the distribution and is equal to the square of the standard deviation.

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