4. Postsurgical infections have been reported to aff ect 2% to 5% of the 16 million patients who undergo surgery in U.S. hospitals. Infections increase the chance of complications and death. Antibiotics given one hour prior to surgery have been shown to reduce the probability of infection. The director of quality improvement has sampled 20 patients per week over the preceding 25 weeks. The data is available in the Chapter07.xls fi le in the Problem07–04 tab. The data collected records whether a patient contracted an infection after surgery.

Create a p chart to analyze performance. Interpret the hospital ’s performance based on your control chart and identify any issues that should be investigated. Assuming the average rate of infection is 3.5%, is the hospital doing a good job?