Random Variables

Often the results of an experiment are quantitative, rather than qualitative; in other words, the outcome of the experiment is a number or numbers. Assume for the moment that the result of the experiment is a single number, say the amount of money we shall be paid as the result of a bet. Then we may want to take into account that, if we receive $50, that is exactly half of $100. For some purposes, we regard a probability of one-fifth of getting $100 as equivalent to a probability of two-fifths of getting $50. We next introduce random variables into our study of probability to make it possible to take a quantitative point of view along those lines.