The A 0f X can be represented by a histogram, or bar chart. as sketched in Fig. 5.6. For each integer X, the probability of X is represented by the area of a rectangle with a base that extends from _ to _ and with a height _ . Thus, the area of the rectangle for which the center of the base is at the integer X is simple _ . An approximating _ is also sketched in Fig. 5.6.