the linear relationship between the two variables. There are three classifications for the correlation of data: 1. Positive correlation: as the explanatory variables. If the relationship between the variables is not linear, then the correlation plot for which r = 1. Figure 1. A perfect positive linear relationship, r = 1. Figure 2. The correlation between two variables can be positive (i.e., higher levels of one variable are associated with higher levels of the other) or negative (i.e., higher.