Problem 5
Research into the relationship between hours of study and gradesshows widely different conclusions. A recent survey of graduateswho wrote the Graduate Management Admissions Test (GMAT) had thefollowingresults.        Â
Hours
Studied           Average
(Midpoint)Â Â Â Â Â Score
40Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 200
50Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 290
65Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 335
75Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 445
85Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 530
105Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 650
95Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 690
          Â
- Run the regression analysis in Excel on this data. Include youroutput with your answer. (Note: You may calculate by hand if youprefer).
- What is the regression equation for this relationship?
- Use the regression equation to predict the average score foreach category of hours studied.
- Plot the original data and the regression line on a scattergram. (You may use Excel).
- How accurate is this regression at predicting GMAT scores basedon hours studied? Explain.
- Use the t statistic to determine whether the CorrelationCoefficient is “significant†at the 95% confidence level.
