Introduction to box diagram

Reprinted from ： What about the box diagram , And what it reflects ？ - You know

Characteristics of box diagram

1. Intuitively and clearly identify abnormal values in the data batch
2. Using the boxplot to judge the skewness and tail weight of the data batch

Not affected by outliers , The discrete distribution of data can be described in a relatively stable way .

（ The source of the picture is self-evident ）.

explain

quantile ：

Sort the values from low to high , Fetch 1/4 The location of , Call it the lower quartile （Q1）; Fetch 1/2 The location of , Call it the median （Q2）; Fetch 3/4 The position of is called the upper quartile （Q3）;

import pandas as pd
num = [1,2,3,4,5,6,7,8]
print(pd.DataFrame(num).describe())

  The red arrow on the top of the figure is Q1 Value , The following is Q3;

And the interquartile distance IQR=Q3-Q1

ceiling =（Q3+1.5IQR,max） Take the minimum , Lower limit =（Q1-1.5IQR ,min) The lion .