title: How to use quantile with dplyr and group_by
body: <p>I have this code below. I'm trying to use quantiles and then subset by groups (years, of which there are two). I think I can do this with <code>dplyr</code>, but it is not working:</p>
  
  <pre><code>Claims6 %&gt;% 
    group_by(year) %&gt;% 
    summarise(ranker = quantile(Expense, prob = c(.10, .30, .50, .80)))
  </code></pre>