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Chapter 8: Q.1 (page 524)

The Gallup Poll interviews 1600people. Of these, 18%say that they jog regularly. The news report adds: "The poll had a margin of error of plus or minus three percentage points at a 95%confidence level." You can safely conclude that

(a) 95%of all Gallup Poll samples like this one give answers within±3%of the true population value.

(b) the percent of the population who jog is certain to be between 15%and21%.

(c) 95%of the population jog between5%and21%of the time.

(d) we can be 95%confident that the sample proportion is captured by the confidence interval.

(e) if Gallup took many samples,95%of them would find that 18%of the people in the sample jog.

Short Answer

Expert verified

(a) 95%of all Gallup Poll samples like this one give answers within±3% of the true population value.

Step by step solution

01

Step-1 Given Information 

Given in the question that,

Number of people(n)=1600

Margin of error=±3%

sample proportion=18%we have to find the correct option.

02

Step-2 Explanation

The margin of error is expected to remain identical for all the confidence intervals because the size of the sample is identical and there would be 95%of the samples that are expected to contain the true value of the population.

Hence, the correct option is (a).

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