80,84,85,86,87,90
minimum = 80
Q1 = 84
Q2 (median) = (85 + 86) / 2 = 171/2 = 85.5
Q3 = 87
maximum = 90
Q1 Q2 Q3
^___^_______^
--80-----| ___|_______ | -----90
^ ^ ^
84 85.5 87
80, minimum, is on outside of box (before Q1)......84 (Q1) is where box starts.....85.5 (median or Q2) is inside the box.....87 (Q3) is the end of the box......90, maximum, is outside the box (after Q3)