An oil producer needs to take a decision about opening a borehole for an oil well

(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.