Much of statistical inference consists of choosing between several available
actions. Generally we do not know for certain which choice will be best
because some important random variable has not yet been observed. For
some values of that random variable one choice is better; and for other values
some other choice is better We can try to weigh the costs and benefits of
the various choices against the probabilities that the various choices turn out
to be best. Utility is one tool for assigning values to the costs and benefits
of our choices. The expected value oi the utility then balances the costs and
benefits according to how likely the uncertain possibilities are.