4. A good customer has just given a microcomputer repairwoman a failed machine. She would like to fix it with the least expenditure of money. One of four parts is probably failed. They are A, B, C, and D, with the cost of replacement $100, $200, $30, and $80, respectively. We use the letters A through D to represent the events that the failure is caused by each of the four parts. Let E be the event that something other than the four parts is causing the computer failure. Three tests, X, Y, and Z, are available to help locate the failed part. To perform the tests requires expenditures of $50, $70, and $80, respectively. If E is discovered or the repairwoman decides to abandon testing, the motherboard can be replaced at a cost of $500. The goal of the analysis is to determine an optimum strategy maintenance that minimizes the expected cost of repair. The strategy will specify the tests to be performed and the actions that should be taken based on the outcomes of the tests. 4. A good customer has just given a microcomputer repairwoman a failed machine. She would like to fix it with the least expenditure of money. One of four parts is probably failed. They are A, B, C, and D, with the cost of replacement $100, $200, $30, and $80, respectively. We use the letters A through D to represent the events that the failure is caused by each of the four parts. Let E be the event that something other than the four parts is causing the computer failure. Three tests, X, Y, and Z, are available to help locate the failed part. To perform the tests requires expenditures of $50, $70, and $80, respectively. If E is discovered or the repairwoman decides to abandon testing, the motherboard can be replaced at a cost of $500. The goal of the analysis is to determine an optimum strategy maintenance that minimizes the expected cost of repair. The strategy will specify the tests to be performed and the actions that should be taken based on the outcomes of the tests