<Li> If there are an odd number of data points in the original ordered data set, do not include the median (the central value in the ordered list) in either half . </Li> <Li> If there are an even number of data points in the original ordered data set, split this data set exactly in half . </Li> <Li> The lower quartile value is the median of the lower half of the data . The upper quartile value is the median of the upper half of the data . </Li> <P> This rule is employed by the TI - 83 calculator boxplot and "1 - Var Stats" functions . This rule is also applied by QUARTIL. EXC function in Excel after Office 2010 </P>

How to work out the lower quartile from a set of numbers