In order to calculate this value we must first understand what the lower quartile, median and upper quartile are: the lower quartile is the median of the lower half of the data. The \(\frac{(n+1)}{ ...

In the example above ... so to find the lower quartile, find \(\frac{1}{4}\) of 40, which is the 10th value. Reading from the graph, the lower quartile is 38. To find the upper quartile, find ...