What Is the Correct Equation for Computing the Expected Value

Multiple Choice

What is the correct equation for computing the expected value of perfect information (EVPI) ?

A) EVPI = expected value under risk for best alternative - expected value under certainty.
B) EVPI = expected value under certainty - expected value under risk for best alternative.
C) EVPI = expected value with sample information - expected value without sample information.
D) EVPI = expected value without sample information - expected value with sample information.
E) none of the above