The mean

• The mean is the average of the data points. Can be calculated by: \[\bar{x} = \frac{\mbox{sum of all observations}}{\mbox{ total number of observations} }\]
• The mean can also be denoted \(\bar{y}\).
• Used for quantitative data. 
• For example a nurse measured a patient’s temperature (in degrees Celcius) \(4\) times \( ( 37.2\), \(37.5\), \(37.1\), \(37.3)\), the mean temperature will be:
\begin{eqnarray*}
\bar{x} &=& \frac{ \mbox{sum of all observations}}{\mbox{total number of observations} }\\
&=&\frac{37.2+ 37.5+ 37.1+ 37.3}{4} \\
&=& 37.275 \\
&\approx& 37.3^\circ\mbox{C}
\end{eqnarray*}