Engineering Homework Help

Need help with my Engineering question – I’m studying for my class.

Discuss the effectiveness of the following sampling designs:

A research company obtains a sample for a focus group through organized groups such as church groups, clubs, and schools. The organizations are paid for securing respondents; no individual is directly compensated.

A citizen’s group interested in generating public and financial support for a new university basketball arena prints a questionnaire in area newspapers. Readers return the questionnaires by mail.

A department store that wishes to examine whether the store is losing or gaining customers draws a sample from its list of credit card holders by selecting every tenth name.