Evaluate the following survey designs:

a. A researcher suggests mailing a small safe (a metal file box with a built-in lock) without the lock combination to respondents, with a note explaining that respondents will be called in a few days for a telephone interview. During the telephone interview, the respondent is given the combination and the safe may be opened.

b. A shopping mall that wishes to evaluate its image places packets including a questionnaire, cover letter, and stamped return envelope in the mall where customers can pick them up if they wish.

c. An e-mail message is sent to individuals who own computers, asking them to complete a questionnaire on a Web site. Respondents answer the questions and then have the opportunity to play a slot-machine game on the Web site. Each respondent is guaranteed a monetary incentive but has the option to increase it by playing the slot-machine game.

d. A mall intercept interviewing service is located in a regional shopping center. The facility contains a small room for television and movie presentations. Shoppers are used as sampling units. However, mall intercept interviewers recruit additional subjects for television commercial experiments by offering them several complimentary tickets for special sneak previews. Individuals contacted at the mall are allowed to bring up to five guests. In some cases the complimentary tickets are offered through ads in a local newspaper.

e. Time magazine opts to conduct a mail survey rather than a telephone survey for a study to determine the demographic characteristics and purchasing behavior of its subscribers.