If you were conducting a telephone survey of households using random digit dialing numbers and you determined that you needed a sample size of 1,100, which of the following would be most accurate?
A) You would need to obtain exactly 1,100 telephone numbers to call.
B) You would need to obtain far less than 1,100 telephone numbers because you know that many will not answer or cooperate anyway.
C) You will need some multiple of the 1,100 numbers in order to ensure you account for factors such as numbers that are for business phones, ineligible households (incidence rate), and those numbers dialed whose owners refuse to participate.
D) You will need only a few extra numbers to allow for those who have moved away.
E) You start off with 1,100; there is no way to determine approximately how many numbers you will actually need
Answer: C) You will need some multiple of the 1,100 numbers in order to ensure you account for factors such as numbers that are for business phones, ineligible households (incidence rate), and those numbers dialed whose owners refuse to participate.