# Question

In Case Study 19.1, we learned that about 56% of American adults actually voted in the presidential election of 1992, whereas about 61% of a random sample claimed that they had voted. The size of the sample was not specified, but suppose it were based on 1600 American adults, a common size for such studies.

a. Into what interval of values should the sample proportion fall 68%, 95%, and almost all of the time?

b. Is the observed value of 61% reasonable, based on your answer to part (a)?

c. Now suppose the sample had been of only 400 people. Compute a standardized score to correspond to the reported percentage of 61%. Comment on whether you believe people in the sample could all have been telling the truth, based on your result.

a. Into what interval of values should the sample proportion fall 68%, 95%, and almost all of the time?

b. Is the observed value of 61% reasonable, based on your answer to part (a)?

c. Now suppose the sample had been of only 400 people. Compute a standardized score to correspond to the reported percentage of 61%. Comment on whether you believe people in the sample could all have been telling the truth, based on your result.

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