A decision maker faced with four decision alternatives and four states of nature develops the following profit payoff table. The decision maker obtains information that enables the following probabilities assessments: P(s1) = 0.5, P(s2) = 0.2, P(s3) = 0.2, and P(s4) = 0.1. (a) Use the expected value approach to determine the optimal decision. EV(d1), EV(d2), EV(d3), EV(d4). The optimal decision is. (b) Now assume that the entries in the payoff table are costs. Use the expected value approach to determine the optimal decision. The optimal decision is.