The question states the four relevant covariates, but chooses age as \delta x with \delta being a coefficient of the ages variable, which reflects the affects of age. Why does it specifically use age, and not for example car insurance group which is between 1-20, or is it arbitrary and we are able to assign whatever we want? A bit confused over when to add in \delta x, \alpha x_2, \beta x_3 etc as opposed to just the constant \alpha _i. Additionally in that CMP chapter some tables don't include the bold x term but some do, which also has me a bit confused. TIA!
you need a constant*variable, so here we have a variable age, x, it didn't have to be delta, just some constant the other 3 are factors so we need to note each level, hence the i j and k you have to define your terms so you can choose but you need a single constant for age and the subscripts for each of the factors denoting the levels The bold in the tables is core reading, but please let me know of specific pages and I can check
