Answer:
The numerical value of the correlation between number of classes skipped and grade index is 0.60.
Step-by-step explanation:
In statistics R² is a measure that is used to determine the proportion of variation in the dependent variable that can be explained by the independent variable. The value of R² is compute by squaring the correlation coefficient (<em>r</em>) between the dependent and independent variable.

In this case the dependent variable is the grades and the independent variable is the number of classes skipped.
The R² between the grades and the number of classes skipped is 36% or 0.36.
Compute the value of <em>r</em> as follows:

Thus, the correlation between number of classes skipped and grade index is ±0.60.