title: what quantile types match the 3 definitions of percentile in R
body: <p>There are 3 definitions of percentile:</p>
  
  <ol>
  <li>lowest number greater than x% of y numbers</li>
  <li>smallest number greater than or equal to x% of y numbers</li>
  <li>weighted mean of the percentiles from 1 &amp; 2</li>
  </ol>
  
  <p>Which <code>quantile()</code> argument <code>type</code> match these three definitions?</p>