1. A certain HMO is attempting to show the benefits of managed care to an insurance company.T he H MO believes thatcertain types of doctors are more cost-effective than others. One theory is that certi fication level is an important factor inmeasuring the cost-effectiveness of physicians. To investigate this, the HMO obtained independent random samples of 26physicians from each of the three cer tification levels-- Board certified ( C )； Uncertified, board eligible ( E )； and Uncertified,board ineligible (l)-and recorded the total per-mem ber, per-month charges for each (a total of 26 physicians). In order tocompare the mean charges for the three groups, the data will be subjected to an analysis of variance. Write the nullhypothesis tested by the ANOVA.
(A) H0, μC =μE=μI=O
(B) H0: μC = μE =μI
(C) H0:β1= β2=β3=0
(D) H0: p1= p2 = p3