3. Suppose in a. study of ehelesterol level {1"} among men, .11 '15 the age (years) (If an individual, and I2 (categorical emanate] indicates whether his bmi :> 25 [:1 if yes; =0 otherwise). (3.) Consider two models Y = .50 + lcrl + c; (3) Y = .35 + {ifs-f + e, where :61\" = 2:1 -- E1 where fl is the average age of all individuals in the study. What is the relationship between the parameters .30 and .55? W'hal about '51 and y." [b] Consider another model. Y = .80 + .8135; 'l' .5213 + ,812333332 -I C, [4) when: If is still defined as in (a). The parameters fig and .81 in this model are not the same as those in model (3). interpret the parameters n, 3'31, .32 and u in model [-4) in the study mntext. (Identifying them as intercept and slopes1 er main effects and interaction eect- is not ennugh.) (:1) Based on model (4), illustrate graphically haw the expected ehelcsteml level de pends on age. Specify the dependence by a. function for each bmi category ('2 25, or net]