# Boxplot

I’ve used these quite often, but I never got to understand theoretically.

Well, I thought each is just represented by the quantiles, there are 4 quartiles.

So actually, it really doesn’t work that way, because there are outliers. I got this wrong on the quiz, so it is time to learn.

Basically, the upper and lower need to be caculated, here is a summary $5-number summary:(min,Q_{1},median,Q_{3},max)$ $Lower Outlier Boundary=Q_{1}−1.5IQR$ $Upper Outlier Boundary=Q_{3}+1.5IQR$ $IQR=Q_{3}−Q_{1}$