Refer to given Exercise and the data in Table on cardiac surgery patients. Conduct a risk-adjusted sequential probability ratio test using a false-alarm rate of 0.005. Assume that the chance of failing to detect a decrease in the odds ratio of mortality from 1 to 0.6 is 0.05.
Exercise
The predicted mortality of cardiac surgery patients in an intensive care unit, based on their APACHE score, is found based on a logistic regression model applied to patients over a four-year period. Table 7-32 shows the predictive pre-operative mortality for 25 recent patients, along with the observed outcome after surgery, where a value of 0 indicates that the patient survived while a value of 1 indicates that the patient died.
Construct a risk-adjusted cumulative sum chart for patient mortality to determine if there has been an improvement. (Use the odds ratio under the alternative hypothesis to be Ra = 0.6.) Comment on the performance of the surgical team.
