The outer diameter,

d, of a cylinder is processed on an automatic machine with upper and lower tolerance limits of d + tU and d - tL. The production process follows a normal distribution with mean m and standard deviation s. Oversized cylinders are reworked at the cost of c1 dollars each. Undersized cylinders are salvaged at the cost of c2 dollars each. Develop the decision tree, and determine the optimal setting d for the machine.