A physician and president of a Tampa Health Maintenance Organization (HMO)are attempting to show the benefits of managed health care to an insurance company.The physician believes that certain types of doctors are more cost-effective than others.To investigate this,the president obtained independent random samples of 20 HMO physicians from each of 4 primary specialties - General Practice (GP),Internal Medicine (IM),Pediatrics (PED),and Family Physicians (FP)- and recorded the total charges per member per month for each.A second variable which the president believes influences total charges per member per month is whether the doctor is a foreign or USA medical school graduate.To investigate this,the president also collected data on 20 foreign medical school graduates in each of the 4 primary specialty types described above.Altogether,information on charges for 40 doctors (20 foreign and 20 USA medical school graduates)was obtained for each of the 4 specialties.Which of the following tests will be the most appropriate to find out if the primary specialty and the origin of medical school degree interact to affect the charges?

Question

Quizplus · Accepted Answer

The most appropriate test to determine if there is an interaction effect between primary specialty and origin of medical school degree on charges is a two-way ANOVA F test for interaction effect. This will allow the analysis of the combined effects of both factors on charges, as well as whether there is a significant interaction effect between the two. A one-way ANOVA F test for interaction effect is not appropriate here because it only tests for the effect of a single factor, and does not take into account the influence of the other factor. The Tukey-Kramer multiple comparisons procedure for one-way ANOVA is not appropriate for testing interaction effects, as it is only used to compare means of multiple groups within a single factor.

A Physician and President of a Tampa Health Maintenance Organization