A study of the effect of different types of anesthesia on the length of postoperative hospital stay yielded the following for cesarean patients:

Group A was given an epiduralMS.
Group B was given an epidural.
Group C was given a spinal.
Group D was given general anesthesia.
The data are presented in Table 6.28. In general, the general anesthetic is considered to be the most dangerous, the spinal somewhat less so, and the epidural even less, with the MS addition providing additional safety. Note that the data are in the form of distributions for each group.
Table 6.28 Data for Exercise 1 Length of Stay Number of Patients Group A 3 6 4 14 Group B 4 18 5 2 Group C 4 10 5 9 6 1 Group D 4 8 5 12

(a) Test for the existence of an effect due to anesthesia type.

(b) Does it appear that the assumptions for the analysis of variance are fulfilled?
Explain.

(c) Compute the residuals to check the assumptions (Section 6.4). Do these results support your answer in part (b)?

(d) What specific recommendations can be made on the basis of these data? LO.1