20.16 Rolling two dice. Example 2 of Chapter 18 (page 430) gives a probability model for rolling two casino dice and recording the number of spots on each of the two up-faces. That example also shows how to find the probability that the total number of spots showing is five. Follow that method to give a probability model for the total number of spots. The possible outcomes are 2, 3, 4, . . . , 12. Then use the probabilities to find the expected value of the total.