Question 3.38

3.38 Random digit telephone dialing for market research.

A market research firm in California uses random digit dialing to choose telephone numbers at random. Numbers are selected separately within each California area code. The size of the sample in each area code is proportional to the population living there.

  1. What is the name for this kind of sampling design?
  2. California area codes, in rough order from north to south, are
209 213 310 323 408 415 510 530 559 562
619 626 650 661 707 714 760 805 818 831
858 909 916 925 949

Another California survey does not call numbers in all area codes but starts with an SRS of eight area codes. Choose such an SRS. If you use Table B, start at line 132.

cacodes