import numpy as np

 employment = np.array([

     55.70000076,  51.40000153,  50.5       ,  75.69999695,

     58.40000153,  40.09999847,  61.5       ,  57.09999847,

     60.90000153,  66.59999847,  60.40000153,  68.09999847,

     66.90000153,  53.40000153,  48.59999847,  56.79999924,

     71.59999847,  58.40000153,  70.40000153,  41.20000076

 ])

 mean = employment.mean()         #计算平均数

 deviation = employment.std()     #计算标准差

 # 标准化数据的公式: (数据值 - 平均数) / 标准差

 standardized_employment = (employment - mean) / deviation

 print (standardized_employment)  

   [-0.31965231 -0.780123   -0.87650077  1.82207181 -0.03051941 -1.99019768

   0.30144772 -0.16973184  0.23719615  0.84758731  0.18365304  1.00821665

   0.87971351 -0.56595055 -1.07996476 -0.20185762  1.38301845 -0.03051941

   1.2545153  -1.87240259]