A Certain HMO Is Attempting to Show the Benefits of Managed

A certain HMO is attempting to show the benefits of managed health care to an insurance company. The HMO believes that certain types of doctors are more cost-effective than others. One
Theory is that both primary specialty and whether the physician is a foreign or USA medical school
Graduate are an important factors in measuring the cost-effectiveness of physicians. To investigate
This, the president obtained independent random samples of 40 HMO physicians, half foreign
Graduates and half USA graduates, from each of four primary specialties-General Practice (GP) ,
Internal Medicine (IM) , Pediatrics (PED) , and Family Physician (FP) -and recorded the total
Per-member, per-month charges for each. Thus, information on charges were obtained for a total
Of n = 160 doctors. The sample mean charges for each of the eight categories are shown in the
Table. $\begin{array}{ccc}\hline \text { Primary Specialty } & \text { Foreign Grad } & \text { USA Grad } \\\hline \text { GP } & 39.00 & 41.40 \\\text { IM } & 52.90 & 50.60 \\\text { PED } & 21.30 & 23.10 \\\text { FP } & 32.80 & 36.60 \\\hline\end{array}$

What type of design was used for this experiment?

A) $4 \times 2$ factorial design with 20 replications
B) completely randomized design with eight treatments
C) $2 \times 2$ factorial design with 160 replications
D) completely randomized design with two treatments