python 绘制正态曲线的示例

 import numpy as np import matplotlib.pyplot as plt import math # Python实现正态分布 # 绘制正态分布概率密度函数 u = 0  # 均值μ u01 = -2 sig = math.sqrt(0.2) # 标准差δ sig01 = math.sqrt(1) sig02 = math.sqrt(5) sig_u01 = math.sqrt(0.5) x = np.linspace(u - 3*sig, u + 3*sig, 50) x_01 = np.linspace(u - 6 * sig, u + 6 * sig, 50) x_02 = np.linspace(u - 10 * sig, u + 10 * sig, 50) x_u01 = np.linspace(u - 10 * sig, u + 1 * sig, 50) y_sig = np.exp(-(x - u) ** 2 /(2* sig **2))/(math.sqrt(2*math.pi)*sig) y_sig01 = np.exp(-(x_01 - u) ** 2 /(2* sig01 **2))/(math.sqrt(2*math.pi)*sig01) y_sig02 = np.exp(-(x_02 - u) ** 2 / (2 * sig02 ** 2)) / (math.sqrt(2 * math.pi) * sig02) y_sig_u01 = np.exp(-(x_u01 - u01) ** 2 / (2 * sig_u01 ** 2)) / (math.sqrt(2 * math.pi) * sig_u01) plt.plot(x, y_sig, "r-", linewidth=2) plt.plot(x_01, y_sig01, "g-", linewidth=2) plt.plot(x_02, y_sig02, "b-", linewidth=2) plt.plot(x_u01, y_sig_u01, "m-", linewidth=2) # plt.plot(x, y, 'r-', x, y, 'go', linewidth=2,markersize=8) plt.grid(True) plt.show()