The city of Richmond is conducting a feasibility study to determine if a high-speed commuter rail system should be added. The number of people commuting into Richmond to work each morning for the past six months are given below: January 2,749,876

February 3,293,874
March 4,923,940
April 3,531,890
May 2,309,870
June 3,103,210
The city will round each month's commuter numbers to the nearest million before finding the total. What is the estimated commuter traffic over the past 6 months?

The survey of study habits and attitudes (ssha) is a psychological test that measures the motivation, attitude toward school, and study habits of students, scores range from 0 to 200. the mean score for u.s. college students is about 115, and the standard deviation is about 30. a teacher who suspects that older students have better attitudes toward school gives the ssha to 55 students who are at least 30 years of age. the mean score is 113.2. assume the population standard deviation is 30 for older students what is the margin of error for a 95% confidence interval for the population mean score for a. older students? b. compute the 95% confidence interval for the population mean score for older students. c. compute the 99% confidence interval for the population mean score for older students. d. compute the 88% confidence interval for the population mean score for older students.