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Chapter 8: Q. 20 (page 483)

An online poll posed the following question:

It is now possible for school students to log on to Internet sites and download homework. Everything from book reports to doctoral dissertations can be downloaded free or for a fee. Do you believe that giving a student who is caught plagiarizing an F for their assignment is the right punishment?

Of the 20,125people who responded, 14,793clicked 鈥淵es.鈥� That鈥檚 73.5%of the sample. Based on this sample, a 95%confidence interval for the percent of the population who would say 鈥淵es鈥� is 73.5% 卤0.61. Which of the three inference conditions is violated? Why is this confidence interval worthless?

Short Answer

Expert verified

The inference conditions violated are:

Random, Voluntary response sample.

Step by step solution

01

Given Information

Violated inference condition

Three inference conditions: Normal, Independent, Random

The condition of Random was violated, because the sample is collected by an online poll which results in a voluntary response sample and thus not a random sample.

02

Explanation

We should point out that the sample of 20,125people is made up of people who elected to participate, making it a voluntary response sample.

Because persons with the strongest opinions are more likely to engage in voluntary response sampling, the population results are likely to diverge significantly from the sample results.

Because the percentage of 73.5percentage . is not a credible measurement for the population percentage, the confidence interval is unlikely to contain the true value of the population proportion.

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Most popular questions from this chapter

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