Tutorial 8

1.

Table 3.10 on Page 76 shows the scores in the final examination F and the scores in two preliminary examinations P1 and P2 for 22 students in a statistics course. Download the dataset from the class website.

(a). Fit a multiple linear regression model for F, P1 and P2, store the ordinary residuals, standardized residuals, studentized residuals, the leverages, and fits.

(b). Draw a matrix plot for F, P1, and P2. What conclusions can you make about the relationship between F, P1 and P2? (c). Draw a matrix plot for the standardized residuals, P1 and P2. What conclusions can you make about the standardized residuals, P1 and P2? Compare it with that in (b).

(d) Draw the Q-Q plot, index plot, histogram, and the plot against fits of the standardized residuals. Check the model assumption violations based on these (e) (f) (g) residual plots.

Draw the plot of the standardized residuals against the studentized residuals. What can you find out from this plot? Draw the plot of F against fits. What can you find out from this plot? What is the correlation coefficient between F and fits?

Draw the index plot of the leverages. Detect any high leverage points.

4/29/2020 ST3131, Tutorial 8 1