In decision-making problems, one is often faced with making decisions based upon phenomena
that have uncertainty associated with them. This uncertainty is caused by inherent
variation due to sources of variation that elude control or the inconsistency of natural
phenomena. Rather than treat this variability qualitatively, one can incorporate it into
the mathematical model and thus handle it quantitatively. This generally can be accomplished
if the natural phenomena exhibit some degree of regularity, so that their variation
can be described by a probability model. The ensuing sections are concerned with methods
for characterizing these probability models.
