2 a)Simple regression of sales revenue in dollars (Y) generated by a salesperson in his/her first year of completed service on the salesperson’s aptitude test score (X) SUMMARY OUTPUT Regression Statistics Multiple R0.99259487 R Square0.985244576 Adjusted R Square0.98487569 Standard Error6705.40139 Observations42 ANOVA dfSSMSFSignificance F Regression11.20089E+111.20089E+112670.8675143.02206E-38 Residual40179849631244962407.8 Total411.21887E+11 Coeffi cientsStandard Errort StatP-valueLower 95%Upper 95%Lower 95.0%Upper 95.0% Intercept71421.115752324.60538130.723974191.94267E-2966722.9130276119.3184766722.9130276119.31847 Aptitude Test Score14961.52033289.500657251.680436483.02206E-3814376.4176715546.6229814376.4176715546.62298 1 b)Estimated conditional expectation function E(Y/X)=71421.11575+14961.52033X c)90% confidence interval forβ22 ¿β2±t0.9,n−2SEβ2 ¿14961.52033±1.684∗289.5006572 ¿14961.52033±487.5191067 Lower 90%¿14474.00 Upper 90%¿15449.04 d)Hypothesis test Step 1: specifying the hypothesis Null hypothesis,H0=0 Vs Alternative hypothesis,H1>0 1Astrid, Gerhard and Maria, "Linear Regression Analysis," 776-782. 2Maria and Pantelis, "On the Covariance of Regression Coefficients," 680-701.
3 Step 2: determining the level of significance Level of significance is 5% which meansα=0.05 Step 3: stating the decision rule The decision rule is to rejectH0if the observedpvalue<0.05 Step 4: calculating the test statistic The test statistic has been calculated using excel and displayed in the regression model table above The coefficient’sp¿value=3.0221∗10−38 Step 5: making the decision Since thepvalueis less than 0.05, we rejectH0and conclude that at 95% significance level there is a significant positive linear relationship between sales revenue generated and aptitude test score. Step 6: interpreting the decision From the decision we can interpret that the aptitude test score of a salesperson indeed affects the sales revenue generated in a positive manner. e)The coefficient of determination is 0.9852 This means that 98.52% of change in sales revenue generated is affected by the relationship between aptitude test score of a salesperson and sales revenue generated.
4 References Astrid, Gerhard, and Maria. 2010. "Linear Regression Analysis."Dtsch Arztebl Int107(44), 776-782. Maria, and Pantelis. 2015. "On the Covariance of Regression Coefficients."Journal of Statistics5(7), 680- 701.