title: How to properly apply RowMeans()? "X is not numeric" error
body: <p>I have two columns within <code>OtherIncludedClean</code>, and I would like to add another column of <code>OtherIncludedClean$Mean</code>; however, my efforts are in vain. </p>
  
  <p>I have tried:</p>
  
  <pre><code>OtherIncludedClean$mean &lt;- rowMeans(OtherIncludedClean, na.rm = FALSE, dims = 1) 
  </code></pre>
  
  <p>But, the above reports the error: </p>
  
  <blockquote>
    <p>"Error in base::rowMeans(x, na.rm = na.rm, dims = dims, ...) : 
      'x' must be numeric"</p>
  </blockquote>
  
  <p>I have also attempted:
   <code>OtherIncludedClean$mean &lt;- apply(OtherIncludedClean, 1, function(x) { mean(x, na.rm=TRUE) })</code></p>
  
  <p>Which reports this error:</p>
  
  <blockquote>
    <p>"1: In mean.default(X[[i]], ...) :
      argument is not numeric or logical: returning NA"</p>
  </blockquote>
  
  <p>For all 141 rows.</p>
  
  <p>Any and all help appreciated. Thank you . </p>
  
  <p>My columns are <code>"X__1"</code> and <code>"X__2"</code></p>