统计思维:程序员数学之概率统计(第二版)

    1. from: https://github.com/AllenDowney/ThinkStats2
    1.  thinkstat2.py       line 2643
type_map = dict(byte=int, int=int, 
long=int, float=float, double=float)
{'int': <type 'int'>, 'double': <type 'float'>, 
'byte': <type 'int'>, 'float': <type 'float'>, 
'long': <type 'int'>}