In a sample of 200 households, the mean number of hours spent on social networking sites during the month of January was 55 hours. In a much larger study, the standard deviation was determined to be 7 hours. Assume the population standard deviation is the same. What is the 99% confidence interval for the mean hours devoted to social networking in January?

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Lily Arroyo

22 April, 23:08

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Ben Snow · Answer 1

99% Confidence Interval = 55 + or - 2.58 x 7/sqrt (200) = 55 + or - 2.58 x 0.495 = 55 + or - 1.277 = 53.773 or 56.227