The QC department at Hershey Mechanical wants to estimate the average useful life of the new O-ring seals that the company has just put on the market. A simple random sample of 25 O-rings produces a sample average life of 1560 hours. The sample standard deviation is 68 hours.
a. Construct and interpret a 95% confidence interval estimate of average useful life for the full population of O-rings produced by the company.
b. For your interval in part a, identify the margin of error and the standard error term.