A researcher was interested in how students’ Graduate Record Examinations scores (GREQQuantitative and GREV-Verbal) predict college students’ graduate school Grade Point Average (GGPA). He collects data from 30 college students. The GRE Quantitative (X1) and GRE Verbal (X2) scores can range from 400-1600 (Note. This is the old GRE score scale). GGPA (Y) can range from 0.00 to 4.00.
Data from Excel:
| GREQ | GREV | GGPA |
| 625 | 540 | 2.16 |
| 575 | 680 | 3.60 |
| 520 | 480 | 2.00 |
| 545 | 520 | 2.48 |
| 520 | 490 | 2.88 |
| 655 | 535 | 3.44 |
| 630 | 720 | 3.68 |
| 500 | 500 | 2.40 |
| 605 | 575 | 3.76 |
| 555 | 690 | 2.72 |
| 505 | 545 | 2.96 |
| 540 | 515 | 2.08 |
| 520 | 520 | 2.48 |
| 585 | 710 | 2.16 |
| 600 | 610 | 4.00 |
| 625 | 540 | 2.16 |
| 575 | 680 | 3.60 |
| 520 | 480 | 2.00 |
| 545 | 520 | 2.48 |
| 520 | 490 | 2.88 |
| 655 | 535 | 3.44 |
| 630 | 720 | 3.68 |
| 500 | 500 | 2.40 |
| 605 | 575 | 3.76 |
| 555 | 690 | 2.72 |
| 505 | 545 | 2.96 |
| 540 | 515 | 2.08 |
| 520 | 520 | 2.48 |
| 585 | 710 | 2.16 |
| 600 | 610 | 4.00 |
a. Write out the regression equation using both independent variables for this set of data.
b. In your own words, interpret the intercept and regression coefficients for your equation.
c. Which of the two independent variables contributes more weight to the regression equation? In other words, which independent variable contributes more to the explanation of the dependent variable variability? Justify why you believe your answer is correct
d. Report and interpret the Pearson Correlation coefficients between GGPA & GREQ, GGPA & GREV, and GREQ & GREV
e. What proportion of variance in graduate grade point average can be accounted for by the variability in the quantitative GRE and verbal GRE scores in combination?
