Statistical power is the probability of rejecting a false null hypothesis. It is represented on the graph below as 1 - β. Remember that the area under the curve of any graph represents relative frequency, or probability. We can calculate the statistical power of a test by determining the probability our sample mean falling into the solid blue (1 - β) area under the curve.

We can either learn how to calculate statistical power or move ahead to a discussion of the factors that influence statistical power.