1) For a confidence level of 92%, find the Z-critical value 2) If n = 500...

1) For a confidence level of 92%, find the Z-critical value

2) If n = 500 and ˆpp^ (p-hat) = 0.7, construct a 99% confidence interval.

3) Insurance companies are interested in knowing the population percent of drivers who always buckle up before riding in a car. They randomly survey 405 drivers and find that 299 claim to always buckle up. Construct a 80% confidence interval for the population proportion that claim to always buckle up.

4) A political candidate has asked you to conduct a poll to determine what percentage of people support her. If the candidate only wants a 2% margin of error at a 95% confidence level, what size of sample is needed? Give your answer in whole people.

5) SAT scores are distributed with a mean of 1,500 and a standard deviation of 300. You are interested in estimating the average SAT score of first year students at your college. If you would like to limit the margin of error of your 95% confidence interval to 25 points, how many students should you sample?

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find the critical value Z α/2 when the confidence level is 92%.

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