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, where A and B are 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
F(z)={█(0.65253 if z=1,@0.34747 if z=0,@0 otherwise )┤
Some random variables have distributions that appear so frequently that the distributions are given names. For example, a random variable Z that takes only two values 0 and 1 with Pr(Z=1)=p(such as Z in Example 3.1.6 with p= 0.65252) has a Bernoulli distribution with parameter p. we conclude this section with illustrations of two additional discrete distributions that arise often.