Question: It is reported that the national success rate for a particular operation is 85 percent.

You are asked to check for a given hospital whether the success experience at your hospital is similar or different than the national average.

You take a random sample of 150 of these procedures and determine whether they are successful or not based on a chart review and use an expert review panel to determine the success or failure of the procedure under study.

The panel reports that in the sample of 150 records 92 of these procedures were successful operations.

Based on the data above answer the following questions:

a) What number of successful operations would you expect to find in a review of 150 records in your hospital if your rate is the same as the national average?

b) Place a 95% confidence interval on the true population proportion of successful operations based on the observed results of your sample of 150.

c) Carry out a test of significance between the national success percent (assuming the national percent success as a standard or null value) and the actual percent success as seen in your sample (a = 0.05)