Which of the following has NOT been shown to be effective in decreasing the number of refusals?

Which of the following has NOT been shown to be effective in decreasing the number of refusals?
 a. The use of incentives
  b. Selling the respondent on the value of the research
  c. Use of experienced interviewers
  d. Guarantees of anonymity
  e. All of the above have been shown to be effective.

Question 2

Household decision roles can be ____, meaning that they relate to tasks affecting the buying decision, such as when and how to purchase.
 a. expressive
  b. titled
  c. habitual
  d. attribute-based
  e. instrumental

Question 3

Refusals are a more important source of nonresponse bias than the not-at-home problem in
 a. personal interviews.
  b. mail surveys.
  c. telephone surveys.
  d. Both a and b.
  e. Not-at-homes are always a more important source of error than refusals.