To understand the behaviour, characteristic, and nature of any variable in a dataset, it is essential to find the distribution of the data on that variable. A distribution is a list or description of all the values of the variable and how often the values are assumed by the variable. In the graphical description of the distribution of a numerical (or quantitative) variable, the values of the variable are presented on the horizontal (x) axis, and the frequency or count measuring how often these values are assumed are presented on the vertical (y) axis. For categorical variables, the distribution may also be presented in the form of a frequency table.