box-and-whisker plot —— Python Data Science Cookook

Sources from : Python Data Science Cookbook case

A box-and-whisker plot is a good companion with the summary statistics to view the statistical summary of the data in hand. Box-and-whiskers can effectively represent quantiles in data and also outliers, if any, emphasizing the overall structure of the data. A box plot consists of the following features:

1. A horizontal line indicating the median that indicates the location of the data 
2. A box spanning the interquartile range, measuring the dispersion   
3. A set of whiskers that extends from the central box horizontally and vertically, which indicates the tail of the distribution

箱形图：最大优点展示数据的结构和异常点

1. 标出中位线
   
2. 箱形扩展到4分位（箱子下沿是数据分布在25%的标识，箱子中间那条线50%，箱子上沿75%）
   
3. 箱子以外的垂直于箱子的线是头尾两端的数据分布
   

iris是sklearn库自带的数据集,