Question 7 (7 marks) Marks A researcher is interested to determine whether a linear relationship exists between the years of experience and the annual salary for engineers. The Microsoft Excel output analysis of these data for twenty-three randomly selected engineers is displayed below. Use these results to answer the questions on the next page. 140 130 Scatterplot of Salary versus Experience 120 110 100 . 90 80 . Salary ($ 000) 70 60 50 40 1 3 5 7 Experience (Years) 9 11 13 Regression Statistics Multiple R 0.902165802 R Square 0.813903134 Adjusted R Square 0.805041378 Standard Error 9.574115488 Observations 23 Coefficients Intercept 49.77532122 Standard Error 5.169886 Experience (Years) 6.695335108 0.698628 t Stat 9.627933 9.583551 P-value 3.75E-09 4.06E-09 Question 7 (continued) Marks a. Write down the least-squares regression equation and interpret its slope in the context of these data. [2] b. Using the regression model equation obtained in part (a), predict the annual salary (in $) for an engineer who has 15 years of experience. [1] C. Use the information from the Excel output, and test (at a 5% level of significance) whether the slope of the linear regression model is different from 0. Include the Hypothesis, Test Statistic, Decision, and Conclusion. [4]