As part of a routine performance review, a hospital administrator has been asked by her supervisor to collect data over the next three weeks to assess whether waiting time in the emergency room (ER) has changed from last year, when average wait time was 127 minutes. The administrator collects a simple random sample of 64 patients that presented at the ER during this time period and records the time between when they checked in at the ER until they were first seen by a physician; the average wait time is 137 minutes, with standard deviation 39 minutes.

a) Compute and interpret a 95% confidence interval for mean ER wait time at the hospital. Based on the interval, is mean ER wait time statistically significantly different from 127 minutes at the = 0.05 level?

b) Would the conclusion in part a) change if the significance level were changed to = 0.01?

c) Suppose that upon seeing the results from part a), the supervisor concludes that ER wait times have increased greatly from last year and that the administrator must be at fault. Present an argument defending the administrator; cite at least two specific points of critique in your argument. Limit your response to no more than eight sentences.