<P> A quartile is a type of quantile . The first quartile (Q) is defined as the middle number between the smallest number and the median of the data set . The second quartile (Q) is the median of the data . The third quartile (Q) is the middle value between the median and the highest value of the data set . </P> <P> In applications of statistics such as epidemiology, sociology and finance, the quartiles of a ranked set of data values are the four subsets whose boundaries are the three quartile points . Thus an individual item might be described as being "in the upper quartile". </P>

How to find the range of a quartile