11. A sales manager wants to investigate the relationship between the salesperson's experience X (independent variable,

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11 A Sales Manager Wants To Investigate The Relationship Between The Salesperson S Experience X Independent Variable 1 (88.79 KiB) Viewed 82 times

11. A sales manager wants to investigate the relationship between the salesperson's experience X (independent variable, in years) and the annual sales Y (dependent variable, in $1000s). A random sample of 10 salespersons is selected and the results are summarized in the ANOVA table below: Degrees of Freedom SS Regression 2272 Residual 8 170 Total 9 2442 1 Coefficients Standard Error Stat p-value Intercept 80 3.075 26.013 0.000 Experience 4 0.387 10.340 0.000 a) What is the estimated regression equation? b) If a salesperson has 2 years of experience, what is the estimated annual sales? c) Is the regression relationship significant? Use the p-value approach and 1% level of significance. d) Compute the coefficient of determination between the years of experience and the annual sales. Interpret the result in the context of the problem. 12. A simple random sample of 60 items provided a sample mean of 10 and a sample standard deviation of 5. a) What is the standard error of the sample mean? b) Provide 99% confidence interval for the population mean. 13. The mean length of a work week for the population of workers was reported to be 39.2 hours. Suppose we would like to take a current sample of workers to see whether the mean length of a work week has changed from the previously reported 39.2 hours. a) State the hypotheses that will help us determine whether a change occurred in the mean length of a work week. b) Suppose a current sample of 112 workers provided a sample mean of 38.5 hours. Use a population standard deviation of 4.8 hours. What is the p-value? c) At 5% significance level, what is your conclusion? d) Repeat the preceding hypothesis test using the critical value approach. ADS