title: getting the standard error of linear regression coefficient using bootstrap
body: <p>I would like to calculate the standard error of linear regression coefficient using bootstrap technique (100 resamples) but the result I got is zero, which is not normal. I think something is wrong with the bootstrap part of the code. Do you know how to fix my code? </p>
  
  <pre><code>x, y = np.genfromtxt("input.txt", unpack=True) 
  
  #regression part
  slope, intercept, r_value, p_value, std_err = stats.linregress(x,y)
  print std_err
  
  #bootstrap part of the code
  A = np.random.choice(x, size=100, replace=True)
  B = np.random.choice(y, size=100, replace=True)
  slope2, intercept2, r_value2, p_value2, std_err2 = stats.linregress(A,B)
  print std_err2
  </code></pre>
  
  <p><strong>input.txt:</strong></p>
  
  <pre><code>-1.08   -1.07
  -2.62   -2.56
  -2.84   -2.79
  -2.22   -2.16
  -3.47   -3.55
  -2.81   -2.79
  -2.86   -2.71
  -3.41   -3.42
  -4.18   -4.21
  -3.50   -3.48
  -5.67   -5.55
  -6.83   -6.95
  -6.13   -6.13
  -8.34   -8.19
  -7.82   -7.83
  -9.86   -9.58
  -8.67   -8.62
  -9.81   -9.81
  -8.39   -8.30
  </code></pre>