In a sample of 50 households, the mean number of hours spent on social networking sites during the month of january was 45 hours. in a much larger study, the standard deviation was determined to be 8 hours. assume the population standard deviation is the same. which of the statement below best describes that there is a 95% confidence interval for the mean hours devoted to social networking in january? a. the 95% confidence interval ranges from 8 to 45 hours. b. the 95% confidence interval ranges from 40.13 to 45.78 hours. c. the 95% confidence interval ranges from 43.87 to 46.13 hours. d. the 95% confidence interval ranges from 42.78 to 47.22 hours.