As chief engineer for your municipal water supply agency, you need to replace the motors that power your water pumps. A set of used motors are available from another city at a cost of $20,000. The city selling their used motors has also offered to test those motors for you, although they admit their motor testing apparatus is not very reliable. 35% of the time, the test says the motor is good. However, their tests are wrong 60% of the time. Your only other alternative is to buy new motors for $40,000. Use a decision tree to help you decide what plan of action to take.