Question 4 (Marks 10) Comment on the following sampling designs:

a) A motorcycle manufacturer decides to research consumer characteristics by sending 200 questionnaires to each of its dealers. The dealers will then pass on the questionnaire to buyers of this brand, based on their sales records.

b) An advertising executive suggests that advertising effectiveness be tested in the real world. A one-page ad is placed in a magazine. One-half of the space is used for the ad itself. On the other half, a short questionnaire requests that readers comment on the ad. An incentive will be given for the first 1,500 responses.

c) A research company obtains a sample for a focus group through a local sports club. The club is paid for securing respondents but the respondents themselves are not directly compensated.