\begin{definition}[Definition:Raw Moment]
Let $X$ be a random variable on some probability space. 
Then the '''$n$th raw moment of $X$''', usually denoted $\mu'_n$, is defined as: 
:$\mu'_n = \expect {X^n}$
where $\expect X$ denotes the expectation of $X$.
That is, the '''$n$th raw moment of $X$''' is its $n$th moment about $0$. 
The '''first raw moment of $X$''' is the mean of $X$, and is instead usually denoted $\mu$.
\end{definition}