问题: Susan Su is not sure what she should do. She can either build a triplex, build a duplex, or simply do nothing. Before doing so, she is considering the possibility of conducting a study to gather additional information about the rental market or not. If she gathers additional information, the results could be either favorable or unfavorable rental market but it would cost her $3,000 to gather the information. Susan believes that there is a 50-50 chance that the information will be favorable. If the rental market is favorable, Susan will earn $15,000 with the triplex or $5,000 with the duplex. Susan doesn't have the financial resources to do both. With an unfavorable rental market, however, Susan could lose $20,000 with the triplex or $10,000 with the duplex. Without gathering additional information, Susan estimates that the probability of a favorable rental market is 0.7. However, if a study is conducted and the result turns out to be favorable, then the probability of a favorable rental market would increase (from 0.7) to 0.9. Furthermore, given an unfavorable result from the study, the probability of a favorable rental market would decrease to 0.4. Of course, Susan could forget all of these numbers and do nothing. (a) Develop a decision tree for Susan Su. (b) Label on the tree the decision alternatives, states of nature, probabilities, and profits. Calculate all necessary values and put them on your diagram. What is your advice to Susan? [Note: You should put all necessary symbols in your decision tree diagram to denote your decision process. -------------- 我作到目前的部分 图片有画了 1.1.是说SUSAN认为调查结果有50%机会是出R，50%会是R* 2.2. SUSAN没有做调查，估计将来实际是好市场F的机会是70%，坏市场F*的机会是30% 如果有做调查，调查结果是好的，而实际结果也是好的机会率，P(F|R) = 90% 结论想问的是说 该不该做调查 做调查的话，预期收益是$2750元，不做调查预期收益是$4500 但是2750是包括了3000元的调查费用 所以计算EVSI (expected value of sample information)的话，要把3000加回去 变成做调查比不做调查好1250元了 那麽应不应该做调查呢? --

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