Hotel managers wish to learn the average length of stay of all visitors that are senior citizens. A statistician determines that to calculate a 90% confidence level estimate of the average length of stay to within +/- 1.5 days, a total of 65 senior visitors’ check-in/check-out records will have to be examined. How many records should be looked at to obtain a 90% confidence level estimate to within +/- 0.5 days?