Question

Identify the sampling techniques​ used, and discuss potential sources of bias​ (if any). Explain.

1. In​ 1965, researchers used random digit dialing to call 1200 people and ask what obstacles kept them from eating healthier.

A. Simple random sampling was​ used since each number had an equal chance of being​ dialed, so all samples of 1200 phone numbers had an equal chance of being selected.

B. Cluster sampling was​ used since the phone numbers were divided into​ groups, several groups were​ selected, and each number in those groups was called.

C. Convenience sampling was​ used since the 1200 phone numbers that were easiest to reach were selected.

D. Systematic sampling was​ used since phone numbers were selected from a list using a fixed interval between phone numbers.

2. After a hurricane​, a disaster area is divided into 200 equal grids. Fifty of the grids are​ selected, and every occupied household in the grid is interviewed to help focus relief efforts on what residents require the most.

A. Stratified sampling is​ used, since the disaster area is divided into​ grids, and a random sample is taken from each grid.

B. Cluster sampling is​ used since the disaster area is divided into​ grids, and some of those grids are selected and everyone in those grids is interviewed.

C. Stratified sampling is​ used since the disaster area is divided into​ grids, and some of those grids are selected and everyone in those grids is interviewed.

D. Cluster sampling is​ used, since the disaster area is divided into​ grids, and a random sample is taken from each grid.

3. Wheat is planted on a 50​-acre field. The field is divided into​ one-acre subplots. A sample is taken from each subplot to estimate the harvest.

A. Simple random sampling is​ used since each sample of wheat plants of the same amount has the same chance of being selected

B. Convenience sampling is​ used since the wheat plants closest to the barn are sampled

C. Cluster sampling is​ used, since the field is divided into​ subplots, a number of subplots are​ selected, and every wheat plant in the selected subplots is sampled.

D. Stratified sampling is​ used, since the field is divided into subplots and a random sample is taken from each subplot.

4. Chosen at​ random, 530 customers at a car dealership are contacted and asked their opinions of the service they received.

A. Convenience sampling is​ used, since the business is selecting from its customers that are easiest to reach.

B. Stratified sampling is​ used since the population of customers is divided into groups and a random sample is selected from each group.

C. Simple random sampling is​ used, since the business is selecting from its customers at​ random, and all samples of 530 customers have an equal chance of being selected.

D. Systematic sampling is​ used since customers are selected at fixed intervals.

E. Cluster sampling is​ used, since the population of customers is divided into groups and several groups are selected and all of their members sampled.

Answer 1

1. In​ 1965, researchers used random digit dialing to call 1200 people and ask what obstacles kept them from eating healthier.

A. Simple random sampling was​ used since each number had an equal chance of being​ dialed, so all samples of 1200 phone numbers had an equal chance of being selected.

2. After a hurricane​, a disaster area is divided into 200 equal grids. Fifty of the grids are​ selected, and every occupied household in the grid is interviewed to help focus relief efforts on what residents require the most.

B. Cluster sampling is​ used since the disaster area is divided into​ grids, and some of those grids are selected and everyone in those grids is interviewed.

Non-coverage bias might occur while using this type of sampling because some grids do not represent the whole population.

3. Wheat is planted on a 50​-acre field. The field is divided into​ one-acre subplots. A sample is taken from each subplot to estimate the harvest.

D. Stratified sampling is​ used, since the field is divided into subplots and a random sample is taken from each subplot.

4. Chosen at​ random, 530 customers at a car dealership are contacted and asked their opinions of the service they received.

A. Convenience sampling is​ used, since the business is selecting from its customers that are easiest to reach.

Sampling bias would be there because sample does not seem to be the representative of the whole population.