Ch18P1 - Chapter 18 Sampling Distribution Models Exercise...

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Chapter 18 Sampling Distribution Models
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Exercise In November 2005, the Harris Poll asked 889 U.S. adults “Do you believe in ghosts?” 40% said they did. At almost the same time, CBS News polled 808 U.S. adults and asked the same question. 48% of their respondents said they believed. Was any one poll wrong?
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The answer is No The reason is because each survey is based on a different sample of about 800 - 900 people. The proportions vary from sample to sample because the samples are composed of different people.
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Think, Show, Tell, and ? Now we have to Imagine. We want to imagine the results from all the random samples of size 800 that we didn’t take. What would the histogram of all the sample proportions look like?
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Histogram for Example For ghost example, where do you expect the center of that histogram to be? Of course, we don’t know the answer to that. But we know that it will be at the true proportion in the population, and we call that p. It should be no surprise that we
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Ch18P1 - Chapter 18 Sampling Distribution Models Exercise...

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