\begin{block}{Scatter plot}
\emph{Scatter plots} are used to investigate the relationship between two numerical variables. \\

The value of one variable is on the y-axis (vertical) and the other on the x-axis (horizontal). \\

When one of the variable is an explanatory variable and the other one is a response variable, the response variable is always on the y-axis and the explanatory variable on the x-axis.
\end{block}

\begin{block}{Response variables and explanatory variables}
For every subject, the value of an \textbf{explanatory variable} will influence what value the \textbf{response variable} receives.
\end{block}