title: What is the difference between binom.mean() and n*p for a given binomial distribution in Python?
body: <p>I have created a binomial distribution using Scipy module 
  <code>wend = stats.binom.pmf(np.arange(4),3,.868)</code></p>
  
  <p>Now when I compute mean of this distribution using the mean function I get the following result</p>
  
  <pre><code>Mean = wend.mean()
  </code></pre>
  
  <blockquote>
    <p>0.25</p>
  </blockquote>
  
  <p>But if we use the formula of mean for binomial distribution i.e n*p we get 0.86 * 3 i.e </p>
  
  <blockquote>
    <p>2.604</p>
  </blockquote>
  
  <p>Why is there a difference in the above two ?</p>