\begin{definition}[Definition:Simple Random Sample]
Let $P$ be a population.
Let $S \subsetneq P$ be a sample.
Then $S$ is a '''simple random sample''' (of size $n$) {{iff}} it fulfils the following criteria:
* The process used to select the individuals of $S$ from $P$ was random;
* Every individual in $P$ had an equal chance of being selected to be in $S$;
* Every $n$-combination of $P$ had an equal chance of being constructed as a potential $S$.
\end{definition}