Chapter 5.1, Problem 29E

(a)

To determine

To Explain: the under coverage may lead to bias in this study and likely direction of this bias.

Answer to Problem 29E

The sample will under coverage bias would overestimate the proportion of Americans that would help the plan.

Explanation of Solution

Chosen or under coverage bias would exclude part of the population.

The survey is only including the people over the age of 50 whom paying membership dues and therefore the people under the age of 50 are excluded, which is leading to under coverage bias.

People over the age of 50 are the most likely to answer “Yes”, the reason is that they are the most likely to have higher drug costs and therefore they would benefit of the plan. This then implies that the sample with under coverage bias would overestimate the proportion of Americans who would help the plan.

(b)

To determine

To Explain: the wording of the question may lead to bias in this study and likely direction of the bias.

Answer to Problem 29E

The sample with response bias would overestimate the proportion of Americans who help the plan.

Explanation of Solution

Measurement or response bias would use a method which gives different values from the true value.

The questions causes response bias because of the statement “can be helped” in the question, which would affect the people to say “Yes” as some people would generally want to support other people

This then implies that the sample with response bias would overestimates the proportion of Americans who help the plan.