1. To estimate the time required to provide a given laboratory procedure, suppose that we measured the amount of time required when the service was provided on 60 occasions. Based on this sample, we obtained a mean of 20.32 minutes and a standard deviation of 3.82 minutes. What can we say with a probability of 0.95 about the size of the error when we use 20.32 minutes as an estimate of the true average time required to provide the procedure?
2 Suppose that a health plan asserts that a patient hospitalized with coronary heart disease requires no more than 6.5 days of hospital care. However, we believe that a stay of 6.5 days is too low.
To examine the claim of the health plan, assume further that we collected data depicting the lengths of stay of 40 patients who were hospitalized recently with coronary heart disease. The results of the sample are as follows:
5, 8, 9, 12, 7, 9, 10, 11, 4, 7, 8, 5, 8,
13, 11, 10, 6, 5, 8, 9,
5, 12, 7, 9, 4, 8, 7, 7, 11, 5, 8, 10, 5,
8, 2, 11, 3, 6, 8, 7 If (infinity sign) = 0.05, use these data to evaluate the claim by the health plan.