title: Error with ar() function in R - MLE only implemented for univariate series
body: <p>I am getting an error when I try to use the AR function in R. Here is my code:</p>
  
  <pre><code>ord = ar(m2, method = "mle")
  </code></pre>
  
  <p>the <code>m2</code> vector is 186 x 1 and contains prices. </p>
  
  <p>The error I get is <code>"MLE only implemented for univariate series"</code></p>
  
  <p>Any ideas?</p>