Chapter 12, Problem 18E

(a)

To determine

To indicate what kind of sampling strategy is involved and what bias might result.

Answer to Problem 18E

The sampling strategy used in this idea is voluntary response.

Explanation of Solution

It is given in the question that in a large school system with twenty elementary schools, the school board is considering the adoption of a new policy that would require elementary students to pass a test in order to promoted to next grade. The ideas proposed for gathering data is given as: run a poll on the TV news, asking people to dial one of two phones numbers to indicate whether they favour or oppose the plan. In this only, now, four new sampling strategy have been proposed to help the PTA determine whether parents favour enquiring for the test. Thus, the kind of sampling strategy used in this idea is voluntary response. And the bias might result because only those who see the show and feel strongly will call.

(b)

To determine

To indicate what kind of sampling strategy is involved and what bias might result.

Answer to Problem 18E

The sampling strategy used in this idea is voluntary response.

Explanation of Solution

It is given in the question that in a large school system with twenty elementary schools, the school board is considering the adoption of a new policy that would require elementary students to pass a test in order to promoted to next grade. The ideas proposed for gathering data is given as: Hold a PTA meeting at each of the twenty elementary schools and tally the opinions expressed by those who attend the meetings. In this only, now, four new sampling strategy have been proposed to help the PTA determine whether parents favour enquiring for the test. Thus, the kind of sampling strategy used in this idea is voluntary response. While slightly more representative than part a, only strongly motivated parents will attend PTA meetings.

(c)

To determine

To indicate what kind of sampling strategy is involved and what bias might result.

Answer to Problem 18E

The sampling strategy used in this idea is multistage, stratified by elementary school and cluster by grade.

Explanation of Solution

It is given in the question that in a large school system with twenty elementary schools, the school board is considering the adoption of a new policy that would require elementary students to pass a test in order to promoted to next grade. The ideas proposed for gathering data is given as: Randomly select one class at each elementary school and contact each of those parents. In this only, now, four new sampling strategy have been proposed to help the PTA determine whether parents favour enquiring for the test. Thus, the kind of sampling strategy used in this idea is multistage, stratified by elementary school and cluster by grade. Most likely a good design as long as most parents in the class respond.

(d)

To determine

To indicate what kind of sampling strategy is involved and what bias might result.

Answer to Problem 18E

The sampling strategy used in this idea is systematic sampling.

Explanation of Solution

It is given in the question that in a large school system with twenty elementary schools, the school board is considering the adoption of a new policy that would require elementary students to pass a test in order to promoted to next grade. The ideas proposed for gathering data is given as: Go through the district’s enrolment records selecting every $40$ th parent. PTA will go to those homes to interview the people chosen. Send them a survey, and follow-up with a phone call if they do not return the survey within a week. In this only, now, four new sampling strategy have been proposed to help the PTA determine whether parents favour enquiring for the test. Thus, the kind of sampling strategy used in this idea is systematic sampling. And the biasness will occur in this method as this lead to minimal bias in this idea.