A hospital-billing auditor has been inspecting patient bills. While almost all bills contain some errors, the defect rate has been 16%.

A hospital-billing auditor has been inspecting patient bills. While almost all bills contain some errors, the defect rate has been 16%. Calculating the upper and lower limits for the billing process for 99.7% confidence the auditor is looking now for large errors (errors in excess of $250). Among the last 100 bills inspected.