Example 3.1.6 Demands for utilities. The random variable Z in Example 3.1.2 equals 1 if at least one of the utility demands is high, and Z=0 if neither demand is high. Since Z takes only two different values, it has a discrete distribution. Note that {s : Z(s)=1} = A B, whewe A and B aew defined in Example 1.5.2. We calculated Pr(A B)=0.65253 in Example 1.5.2. If Z has p.f. f , than