title: analyzing FFT data for mean frequency?
body: <p>I used numpy fft.fft to analyze some time series data (black) and generate a plot like the following:</p>
  
  <p><a href="https://i.stack.imgur.com/QhZc9.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/QhZc9.png" alt="enter image description here"></a></p>
  
  <p>From the FFT data (in red) i calculated mean frequency by multiplying x*y for each data point and dividing by the number of data points.   Is this correct? or am i misunderstanding what the y-axis means.</p>
  
  <p>if this is incorrect, how are mean and median frequency calculated, or are those not useful metrics? </p>
  
  <p>Thank you for your time and consideration.</p>