To find each quartile of a data set, first sort the data set in ascending order from smallest to largest and find the median [katex] (Q2). [/katex] Find the lower quartile [katex] (Q1) [/katex] by locating the median (central value) of the lower half of the data set, and find the upper quartile [katex] (Q3) [/katex] by locating the median (central value) of the upper half of the data set.