title: Summarise - Error: `n()` must only be used inside dplyr verbs
body: <p>I'm trying to do a very simple count using the following code:</p>
  <pre><code>Bar_data_TEST &lt;- Bar_data %&gt;%
    group_by(metric) %&gt;%
    summarise(n = n())
  
  </code></pre>
  <p>but keep getting the above error and I have no idea why - any ideas?</p>