Chapter 3, Page 30, Figure 3.1

[zeinab-sheikhi]

In the first figure of Figure 3.1, in which the x-axis is easy, and the y-axis is AI, when easy is 1, and AI is 0 we have 1 positive (2 positives are shown in the figure) also when easy is 0, and AI is 1 we have 4 positives(3 positives are shown in the figure).