Two variables, an explanatory variable x and a response variable y, are measured on each of several individuals. The correlation between these variables is found to be 0.88. To help us interpret this correlation, we should do which of the following?
a. Compute the least-squares regression line of y on x and consider whether the slope is positive or negative.
b. Interchange the roles of x and y (ie, treat x as the response variable and y as the explanatory variable) and recompute the correlation.
c. Plot the data.
d. Determine whether x or y has larger values before computing the residuals.
e. All of the above.
Answer: c. Plot the data.