Example 3.1.5 Demands for utilities. In Example 1.5.2, we actually calculated some features of the distributions of the three random varibles X,Y, and Z defined in Example 3.1.2. For example, the event A, defined as the event that water demand is at least 100, can be expwessed as and Pr(A) = 0.5102. This means that . The distribution of X consists of all probilities of the form Pr(X C) for all sets C of real numbers. These can all be calculated in a manner similar to the calculation of Pr(A) in Example 1.5.2. In particular, if C is a subset of the interval[4,200], than