title: using fun.y in ggplot
body: <p>I am an absolute  beginner. So, I apologize for asking basic question. I am trying to plot the minimum value in my dataset. I looked at the following page (<a href="https://stackoverflow.com/questions/30558633/changing-y-scale-when-using-fun-y-ggplot">changing y scale when using fun.y ggplot</a>) and didn't find the solution.</p>
  
  <p>Here's the first code: this works well. It plotsa red dot at the mean.</p>
  
  <pre><code>ggplot(mpg, aes(trans, cty)) +
    geom_point() +
    stat_summary(geom = "point", fun.y = "mean", colour = "red", size = 4)
  </code></pre>
  
  <p>This one doesn't work. Can someone please help me? </p>
  
  <pre><code>ggplot(mpg, aes(trans, cty)) +
    geom_point() +
    stat_summary(geom = "point", fun.ymin = min, colour = "red", size = 50)
  </code></pre>
  
  <p>I am not sure what's going on.</p>