title: Plot margin of pdf plot device: y-axis label falling outside graphics window
body: <p>I tried simply plotting some data in R with the y-axis label horizontal and left of the y-axis tick labels. I thought the code below would work:</p>
  
  <pre><code>set.seed(1)
  n.obs       &lt;- 390
  vol.min     &lt;- .20/sqrt(252 * 390)
  eps         &lt;- rnorm(n = n.obs, sd = vol.min)
  mar.default &lt;- c(5,4,4,2) + 0.1
  par(mar = mar.default + c(0, 4, 0, 0))               # add space to LHS of plot
  pdf("~/myplot.pdf", width=5.05, height=3.8)
  plot(eps,  main  =  "Hello  World!", las=1, ylab="") # suppress the y-axis label
  mtext(text="eps", side=2, line=4, las=1)             # add horiz y-axis label
                                                       # 4 lines into the margin
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/YhQdA.png" alt="my image"></p>
  
  <p>Instead, as you may see, the y-axis label almost fell completely outside of the graphics window. This phenomenon still exists no matter how much I expand the LHS margin. </p>
  
  <p>Q: What am I doing wrong? Is there something I need to do with the <code>oma</code> parameter? What do I need to do to plot things the way I'm intending? I'm a little overwhelmed by all of this!</p>