Random Variables

Abstract

We have seen that the points of a sample space may be very concrete objects such as apples, molecules and people. As such they possess various qualities some of which may be measurable. An apple has its weight and volume; its juicy content can be scientifically measured, even its taste may be graded by expert tasters. A molecule has mass and velocity, from which we can compute its momentum and kinetic energy by formulas from physics. For a human being there are physiological characteristics such as age, height and weight. But there are many other numerical data attached to him (or her) like I.Q., number of years of schooling, number of brothers and sisters, annual income earned and taxes paid, and so on. We will examine some of these illustrations and then set up a mathematical description in general terms.