ABSTRACT
ONE WAY OF ASSESSING an uncertain future is to translate it into a probability distribution of potential outcomes. When all of the potential outcomes are expressed in terms of a single unit—such as amount of money, temperature change, or human population—one can also generate variables such as the mean and standard deviation to describe the distribution. Even when one cannot express the different outcomes in unitary terms, one can still describe the distribution in terms of its central tendency and its extremes: events that one predicts with very high and very low likelihoods, respectively.
