**1. Does it matter which axis is used for a particular set of data on a scatter diagram?**

Not usually. Any connection will be apparent whichever set of data is plotted on a particular axis.

**2. What does r stand for in the study of regression and correlation?**

rstands for the correlation coefficient. The nearer the value of r is to 1 or -1, the closer the points on a scatter diagram are to fitting a straight line.