**4.1 Discrete probability distribution**

A discreet distribution of probability is made up of discrete variables. Specifically, if a random variable is discreet, the probability distribution would be discreet. For a discrete probability distribution, each potential value of a discrete random variable can be correlated with a non-zero probability [9, 10]. Therefore, a discrete probability distribution is also provided in tabular form.

The following example shows that the probability (relative frequency) of someone randomly chosen from the operating theater staff being a non-smoker is 0.45 (**Table 1**).

Note that in the right column, the frequencies (counts) have been turned into relative frequencies (percentage). How you do this:

1.Count the total number of items. In this chart the total is 60.

2.Divide the count (the frequency) by the total number. For example, 27/ 60 = 0.45 or 17/ 60 = 0.28
