aments, choose Check for Updates. Number of Purchase orders Total costs (thousands) 1 875 $312 1 500 2 25 3 800 380 2 300 375 3 500 312 2 700 325 COSTS $500 $450 $400 $350 Cost (Thousands) CO $200 $150 $100 $50 1000 1500 2000 2500 3000 Purchase Order amount 3500 4000 (ii) Use the high-low method to estimate the cost function showing fixed cost and variable cost per purchase order. (iii) Regression analysis reveals that the equation of the best-fitting straight line through the sample point is: Total cost = $183 160+ $46.57 per purchase order. Draw the regression-analysis line on the graph from requirement (i). (iv) Use both the high-low method and regression-analysis cost functions to predict purchasing department cost for a quarter in which Smith places 3 000 purchase orders with suppliers. In which prediction do you have more confidence? Give your reason