Hill (1990) studied the correlations between final exam score in an introductory sociology course and several other variables such as number of absences. The following Pearson r correlation coefficients with final exam score were obtained:

Overall college GPA.................................................    .72

Number of absences..............................................    -.51

Hours spent studying on weekdays ..................    -.11 (not significant)

Hours spent studying on weekends...................     .31

Describe each correlation and draw graphs depicting the general shape of each relationship. Why might hours spent studying on weekends be correlated with grades but weekday studying not be?