title: Error in complete.cases(x) : invalid 'type' (builtin) of argument
body: <p>I am trying to run a shapiro.test on one variable of my DF.</p>
  
  <pre><code>        shapiro.test(chicks.2012)
  </code></pre>
  
  <p>I am getting the following error message </p>
  
  <pre><code>  Error in complete.cases(x) : invalid 'type' (builtin) of argument
  </code></pre>
  
  <p>Please note that the variable is a numeric variable and three (3) values are NAs.. 
  I would be grateful if someone could explain me what it means.</p>
  
  <p>thank you for any help</p>
  
  <p>Simon</p>