title: How do I get the bottom 10% of values in a dataframe column?
body: <p>I have a dataframe (<code>allDat</code>) that looks like the following (but more rows) and I'm trying to subset it to get individuals (samples) with the bottom 10% of Expression:</p>
  
  <pre><code>SampleID    Expression   Gene
  HSB496      14.64295     ENSG00000118271
  HSB261      14.3346      ENSG00000144820
  HSB248      13.48286     ENSG00000167552
  </code></pre>
  
  <p>Here is what I have tried, but I feel like this is wrong or that there may be a better approach at least:</p>
  
  <pre><code>allDat_10 &lt;- subset(allDat, Expression &gt; quantile(Expression, prob = 10/100, na.rm = TRUE))
  </code></pre>