title: as.numeric/as.integer not working in R
body: <p>I'm new to R and trying to do a simple ANOVA. I created a data frame:</p>
  
  <pre><code>MeanTable &lt;- data.frame(Age=c("2","2","2","4","4","4","6","6","6"), 
     Yield=c("12.812","15.17","13.868","24.456","23.444","25.312",
           "21.146","21.63","21.84"),stringsAsFactors = FALSE)
  </code></pre>
  
  <p>And then tried to do an ANOVA, but I got this warning message: </p>
  
  <blockquote>
    <p>Warning messages:
    1: In mean.default(X[[i]], ...) :
      argument is not numeric or logical: returning NA
    2: In mean.default(X[[i]], ...) :
      argument is not numeric or logical: returning NA
    3: In mean.default(X[[i]], ...) :
      argument is not numeric or logical: returning NA</p>
  </blockquote>
  
  <p>So I assume that means I'm meant to use as.numeric to convert the values from factors into numbers. So I did this:</p>
  
  <pre><code>as.numeric(MeanTable$Age)
  is.numeric(MeanTable$Age)
  </code></pre>
  
  <p>But got <code>FALSE</code>. What am I doing wrong? Or is my issue something else entirely?</p>