SPC - 用pandas和matplotlib画X-bar chart

@anniehan333 问到怎么用Python画分组的X-bar控制图，题目如下：（来自她正在编写的书籍）

这是她用MiniTab画的图：

以下是Python实现过程：

主要是用pandas的groupby来实现分组子图

代码整合：

import pandas as pd
import numpy as np
import matplotlib.pyplot as plt


"""字典形式导入数据"""
x1 = {
   
   'Measure_1': [28.4,28.9,29.0,28.4,28.6], 
      'Measure_2': [28.4,29.0,29.1,28.5,28.6], 
      'Measure_3': [28.4,29.0,29.1,28.5,28.6]}   # A测定员
x2 = {
   
   'Measure_1': [28.5,28.8,29.0,28.5,28.6], 
      'Measure_2': [28.4,28.9,29.0,28.5,28.6], 
      'Measure_3': [28.4,28.8,29.0,28.5