Association

Abstract

Measures of association provide a means of expressing the degree or amount of association between two variables, typically named X and Y. Many measures of association are constructed to return values between ±1 (perfect association) and 0 (no association). The closer to 1, the “stronger” the association. Some return values between −1 and 1, so the nature of the association is expressed. Negative values indicate a negative or inverse relationship (Y values decrease as X values increase), while positive values indicate a positive relationship (Y values increase as X values increase). Hypothesis tests are possible for many of the measures of association. They begin by hypothesizing that there is NO relationship between the two variables, or that the measure of association equals 0.