Chapter outline This chapter will look at the use of analytical tools to describe data and to demonstrate the effect that one variable may have on another. The notion of probability will be introduced using examples with which you will probably be familiar. In fact, you will find that you are already fully conversant with the notion and use of probability. Using practical examples, this chapter will demonstrate the use of probability within research. The notion of proof will be examined, and it will be suggested that research seldom proves anything but merely determines the degree to which the results can be trusted.