Arithmetic function in which the domain is the set of the modalities or the values of a statistical attribute.

### Example

Consider a set of ordered pairs corresponding to the data in the table below, which illustrates the evolution of the price of a computer over the years since personal computers first appeared:

Years | 1982 | 1988 | 1994 | 2000 | 2006 |

Price ($) | 4900 | 2950 | 2000 | 1275 | 980 |

These ordered pairs describe a distribution function of the set of years (1982 to 2006) in the set of prices expressed in dollars. The graph of this function, in the form of a line graph, looks like this: