Marketing research firms often contact their respondents by sampling random telephone numbers. Although interviewers currently reach about 76% of selected households, the percentage of those contacted who agree to cooperate with the survey has fallen and is now only 38%. Each household is assumed to be independent of the others.

a) What is the probability that the next household on the list will be contacted but will refuse to cooperate?

b) What is the probability of failing to contact a household or of contacting the household but not getting them to agree to the interview?

c) Show another way to calculate the probability in (b).