TabComp Inc. is a retail distributor for MZB-33 computer hardware and related software. TabComp prepares annual sales forecasts, of which the first six months of the coming year are presented below:

Hardware units Hardware dollars Software Total sales January 130 $390 , 000 $160, 000 $550, 000 February 120 360, 000 140, 000 500, 000 March 110 330, 000 150, 000 480, 000 April 90 270,000 130 , 000 400, 000 May 100 300, 000 125 , 000 425, 000 June 125 375, 000 225, 000 600, 000