Please how do we calculate EMV? I need also explanation

Starting with the finished version of the file for Figure 6.21 for Acme, change the probabilities in cells 89 for P(good), the prior probability of a good market outcome (make it smaller in 0.05 increments), B14 for P(good | good), the conditional probability of having a good prediction, given a good market outcome (make It larger in 0.05 increments), and 815 for P(good | bad), the conditional probability of having a good prediction, given a bad market outcome (make it smaller in 0.05 increments.) For each combination calculate the EMV and decide whether Acme should hire the marketing research firm. Round your answers (in $1,000s) to one decimal place, If necessary. P(good) P(good | good) P(good | bad) Hire firm? EMV 0.40 0.80 0.30 Yes 2 0.35 0.85 0.25 Yes 0.30 0.90 0.20 0.25 0.95 0.15