title: Superscript R squared for legend
body: <p>I want to write a R-squared term for my legend but I do not know how. Could someone help me please?
  My legend syntax is:</p>
  
  <pre><code>legend(2,10, c("BW (MPE=3%, R-squared=0.77)", 
         "MY (MPE=5%, R-squared=0.80)", pch=c(2,3))
  </code></pre>
  
  <p>I would liek to express R-squared as R2 as we normally have in the text.</p>