Comprehensive regression problem in an effort to expend sales programs in the best way to generate sales revenue, the Cordwinn Company has been tracking various costs and sales data. Below is a randomly selected sample of 12 months of data.

Number of Month Sales Dollars Sales Telephone Travel Commissions Calls Costs 1 $650,000 $61,000 3,400 $14,000 10 11 12 23456CORDT2 720,000 66,000 3,500 17,000 660,000 65,000 3,450 16,000 800,000 69,000 3,600 17,500 760,000 66,000 3,420 16,800 690,000 66,500 3,500 16,000 7 850,000 71,000 3,700 19,000 8 880,000 72,500 3,750 19,300 9 770,000 69,000 3,550 18,200 700,000 66,800 3,450 17,200 820,000 73,200 3,800 18,900 840,000 74,000 3,850 19,900