title: How do I tell how good my exponential curve fit is in SciPy?
body: <p>I fit some data using Scipy:</p>
  
  <pre><code>param=expon.fit(data)
  pdf_fitted=expon.pdf(x,loc=param[-2],scale=param[-1])
  plot(x,pdf_fitted,'r')
  hist(data,normed=1,alpha=.3,histtype='stepfilled')
  </code></pre>
  
  <p>And I get a curve that looks like this:</p>
  
  <p><img src="https://i.stack.imgur.com/ohpDK.png" alt="Exponential fit to data"></p>
  
  <p>How do I check how good the fit is (is there a parameter for this?). I'd like a number so I can compare different ways of fitting.</p>