Question

A television network wanted to estimate the proportion of a one-hour time slot that is made up of commercials. The network took random samples of

10
10 one-hour time slots. The following are the sample proportions the network found in
12
12 samples.

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Part A

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​What is the estimated proportion of commercials in all one-hour time slots? Round your answer to the nearest thousandth.

Answer 1

120

Explanation:

Remember, always round sample size up, regardless of the decimal part. Answer: To find a 95% CI with a margin of error no more than ±3.5 percentage points, where the true population proportion is around 42%, you must survey at least 764 people. 10×764 = 7640; presumably the electorate is larger than that. So, then 10 × 12 = 120