Four new sampling strategies have been proposed to help PTV determine whether enough cable subscribers are likely to purchase high-speed Internet service. For each, indicate what kind of sampling strategy is involved and what (if any) biases might result.
a) Run a poll on the local TV news, asking people to dial one of two phone numbers to indicate whether they would be interested.
b) Hold a meeting in each of the 15 towns, and tally the opinions expressed by those who attend the meetings.
c) Randomly select one street in each town and contact each of the households on that street.
d) Go through the company’s customer records, selecting every 40th subscriber. Send employees to those homes to interview the people chosen.