#!/usr/bin/env python3

 #-*- coding:utf-8 -*-

 #############################################

 #File Name: t.py

 #Brief:

 #Author: frank

 #Email: frank0903@aliyun.com

 #Created Time:2018-08-17 23:07:24

 #Blog: http://www.cnblogs.com/black-mamba

 #Github: https://github.com/xiaomagejunfu0903/statistic_notes

 #############################################

 from scipy.stats import t

 from scipy.stats import norm

 import matplotlib.pyplot as plt

 import numpy as np

 df = 2

 rv_t = t(df)

 x = np.linspace(-4,4, 100)

 plt.plot(x,rv_t.pdf(x),'y-',label='df=2')

 x2 = np.linspace(-4,4, 100)

 plt.plot(x2,t.pdf(x2,5),'g--',label='df=5')

 x3 = np.linspace(-4,4, 100)

 plt.plot(x3,t.pdf(x3,10),'b--',label='df=10')

 x4 = np.linspace(-4,4, 100)

 plt.plot(x4,t.pdf(x4,120),'r--',label='df=120')

 x5 = np.linspace(-4,4, 100)

 plt.plot(x5,norm.pdf(x5),'m--',label='std norm',alpha=0.5)

 plt.legend()

 plt.show()