(B), or not (B). The borehole may be dry, Sp, contaminated, Sc (viz.: contains oil as
well as other substances), or may contain oil, So. Expert evaluation assigns a-priori
probabilities to these events of 40%, 31% and 29% respectively. The benefit
associated to the decision of opening up the borehole are estimated as the difference
between the cost of opening the borehole and the income from the oil, and amount
to -£102K (dry well), £20K (contaminated), and £250K (oil).
Perform a prior decision analysis to determine whether it is beneficial to open up
the borehole.