title: Boxplot missing label
body: <p><code>boxplot(smkgp, nsmkgp, main="premature delivery", 
           xlab="gestation", ylim=c(200,400), xlim=c(0,3), 
           horizontal=TRUE, 
           names=c("smoking group", "nonsmoking group"))</code></p>
  
  <p>I'm making a box plot, and there are two groups to be displayed: Smoking group and non smoking group.</p>
  
  <p>But label for non smoking group is missing.
  I tried using par(mar(,,,,) to display the missing label but it didn't work.</p>
  
  <p>How do I fix this problem?</p>
  
  <p>I appreciate your time.</p>
  
  <p><img src="https://i.stack.imgur.com/jyvGm.png" alt="enter image description here"></p>