\begin{definition}[Definition:Mode]
Let $S$ be a set of quantitative data.
The '''mode''' of $S$ is the element of $S$ which occurs most often in $S$.
If there is more than one such element of $S$ which occurs equally most often, it is then understood that each of these is a '''mode'''.
If there is no element of $S$ which occurs more often (in the extreme case, all elements are equal) then $S$ has '''no mode'''
\end{definition}