EX 3.2

• Consider the experiment of dialing a telephone number in a certain area code using a random number dialer.
  • Define a random variable (rv) $Y$ as follows:
    • $Y=1$ if the selected number is unlisted
    • $Y=0$ if the selected number is listed in the directory
  • Examples:
    • If 5282966 appears in the telephone directory, then:
      • $Y(5282966)=0$ (the number is listed).
    • If 7727350 is unlisted, then:
      • $Y(7727350)=1$ (the number is unlisted).
  • A word description of this sort is more economical than a complete listing.
    • We will use such descriptions whenever possible.