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Chapter 7: Q. T7.2 (page 486)

The Gallup Poll has decided to increase the size of its random sample of voters from about 1500 people to about 4000 people right before an election. The poll is designed to estimate the proportion of voters who favor a new law banning smoking in public buildings. The effect of this increase is to

a. reduce the bias of the estimate.

b. increase the bias of the estimate.

c. reduce the variability of the estimate.

d. increase the variability of the estimate.

e. reduce the bias and variability of the estimate.

Short Answer

Expert verified

(c) The effect of this increase is to reduce the variability of the estimate.

Step by step solution

01

Given Information

Right before an election, the Gallup Poll decided to raise the size of its random sample of voters from 1500 to 4000 persons. The purpose of the poll is to determine the percentage of voters who support a new law prohibiting smoking in public places.

02

Explanation for correct option

Because the inaccuracies are produced by the sampling techniques, sample size has no bearing on them. When the sample size is increased, the variability is reduced since a larger sample provides more information about the population and thus better estimates.

As a result, the best solution is (c)

03

Explanation for incorrect option

a. reduce the bias of the estimate is not the answer.

b. increase the bias of the estimate is not the answer.

d. increase the variability of the estimate is not the answer.

e. reduce the bias and variability of the estimate is not the answer.

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COLORAGE
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WHITE5
SILVER8
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