Simple Linear Regression � Supplemental Review Problem

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1 Simple Linear Regression – Supplemental Review Problem We feel that the grade students get on the final exam are related to the amount of studying they do. To explore this, a sample of 17 students was gathered. Grade Hrs Studied 99 8 97 5 94 7 94 6 93 8 92 4 91 7 86 5 85 4 82 6 81 7 80 3 75 2 73 3 73 4 72 2 71 3 Using Minitab, run correlation analysis and simple linear regression to study the relationship between Grade and Hrs Studied. Answer the questions below: a. Analyze the Minitab output to determine the regression equation. b. Find the coefficient of correlation. Interpret this value. c. Does this data provide significant evidence (a lpha =0.05) that the Hours Studied can be used to predict Grade a student gets on the final exam? Also interpret the p - value. d. Predict the exam grade if a person studies 5 hours. e. What is the 95% confidence interval for the mean exam Grade for students studying 7 hours? f. What conclusions are possible using the meaning of ö  0 and ö  1 in this problem? (That is, explain the meaning of the coefficients. ) g. What conclusions are possible using the coefficient of determination (r - squared)? h. What is the standard error? What does it mean? Solution: MINITAB OUTPUT Regression Analysis: Grade versus Hrs Studied
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