title: Including custom text in legend of plot
body: <p>Suppose I have a data that looks like this.</p>
  
  <pre><code>&gt; print(dat)
  V1    V2
  1  1 11613
  2  2  6517
  3  3  2442
  4  4   687
  5  5   159
  6  6    29
  
  # note that V2 is the frequency and V1 does not always start with 1. 
  
  
  &gt; plot(dat,main=title,type="h")
     # legend()??
  </code></pre>
  
  <p>Now what I want to do is to plot histogram, and have the mean
  and standard deviation included as the legend. In the above example the standard deviation equals 0.87 and the mean eauals 1.66.</p>
  
  <p>How can I achieve that automatically in R?</p>