We determined that a sample mean of 5.40 is the value beyond which we reject the null hypothesis in favor of the alternative. This is the value at the solid red line. The light blue sections of the distribution are what were hidden behind the null hypothesis (red) distribution.

All parts of the graph with horizontal white lines represent Type II error (β). This is the proportion of time, or probability, of failing to reject the null hypothesis when it is false (we actually sampled from the distribution in blue). The sections of the graph to the left of the solid red line (critical value) represent the probability of correctly rejecting the null hypothesis when it is false (when we have sampled from a population with less face-to-face social interaction).