Since its release. Bob Aker's 'Cooking to Go' has sold the following number of copies each Q1:
(i). 2X13:200
(ii). 2X14:430
(iii). 2X15:530
(iv).2X16:450
Using these figures and the equation, y (trend) = 500 + 20x, which of the following is the mean seasonal average of sales of Bob Aker's 'Cooking to Go' for Q1 over the last four years?
Calculate all the final and answer and all intermediate workings to 2 dp.