A study is conducted in patient with HIV. Lower CD4 count is associated with advance disease. The researcher is interested in finding out the relation between supplement vitamins and CD4 count. A multiple regression analysis is performed relating CD4 count to the use of suppliments(coded as 1=yes, 0=No)and to the duration of HIV in years between the diagnosis of HIV and the study dates). For the analysis,
Y hat=501.41+12.67(supplement)-30.23(duration of HIV).
a) what is expected CD4 countfor a patient taking supplement who has had HIV for 2.5 years?
b)what is the CD4 count For patient not taking supplement who was diagnosed with HIV at study enrollment?
c)what is the CD4 count for patients not taking supplement who has had HIV for 2.5 years?