Seven Hills Hospital in Visakhapatnam, Andhra Pradesh, commonly conducts stress tests to study the heart muscle after a person has a heart attack. Members of the diagnostic imagine department conducted a quality improvement project with the objective of reducing the turnaround time for stress tests. Turnaround time is defined as the time from when a test is ordered to when the radiologist signs off on the test results. Initially, the mean turnaround time for a stress-test was 68 hours. After incorporating changes into the stress-tress process, the quality improvement team collected a sample of 50 turnaround times. In this sample, the mean turnaround time was 32 hours, with a standard deviation of 9 hours.
1. Construct a 95% confidence interval estimate for the population mean turnover time.
2. Interpret the interval constructed in (a).
3. Do you think the quality improvement project was a success?