$2\mathrm{.}13$ This example is based on a case described by Gold $(2013).$ Joe is considering installing solar panels on the roof of his home in Sun City, Arizona. If he goes forward, he will pay the installation firm but will save money on his electric bill. The amount he will save depends upon the amount of sun that Sun City will receive in the future, but he is not sure how many days of sun will occur. Draw an influence diagram that represents this decision situation. Include his decision, the uncertainty, and the outcome.