title: Plot a poisson distribution graph in python
body: <p>I would like to plot the Poisson function in Python using Matplotlib. The function is (exp(-5)*5^x)/factorial(x)</p>
  
  <pre><code>import numpy as np
  import math
  import matplotlib.pyplot as plt
  
  t = np.arange(0, 20, 0.1)
  d = []
  
  for i in t:
      p = pow(5,i)
      q = p/math.factorial(i)
      d.append(q)
  
  plt.plot( t, np.exp(-5)*d, 'bs')
  plt.show()
  </code></pre>
  
  <p>But I get this error."Only size^1 arrays can be converted to Python scalars". How can I plot this graph? Thanks in advance</p>