This is considered another measure of spread. Used in conjunction with median. Not affected by outliers. Probability THE most important topic in statistics. The entire subject of statistics deals with chance.
Probability is the study of chance.
In general to find probability we often assume all events are equally likely. Question of a Fair Coin or Fair Die. Probability of the Sample Space is 1. Two dice are to be rolled. Random Variables Real Valued Function defined from the Sample Space.