Predicting final exams How well do exams given during the semester predict performance

Chapter 28, Problem 13

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Predicting final exams How well do exams given during the semester predict performance on the final? One class had three tests during the semester. Computer output of the regression gives Dependent variable is Final s = 13.46 R-Sq = 77.7, R-Sq(adj) = 74.1, Predictor Coeff SE(Coeff) t-Ratio P-Value Intercept -6.72 14.00 -0.48 0.636 Test1 0.2560 0.2274 1.13 0.274 Test2 0.3912 0.2198 1.78 0.091 Test3 0.9015 0.2086 4.32 60.0001 Analysis of Variance Source DF SS MS F-Ratio P-Value Regression 3 11961.8 3987.3 22.02 60.0001 Error 19 3440.8 181.1 Total 22 15402.6 a) Write the equation of the regression model. b) How much of the variation in final exam scores is accounted for by the regression model? c) Explain in context what the coefficient of Test3 scores means. d) A student argues that clearly the first exam doesnt help to predict final performance. She suggests that this exam not be given at all. Does Test1 have no effect on the final exam score? Can you tell from this model? (Hint: Do you think test scores are related to each other?)