title: (R) column mean works with one command but not with another
body: <p>I've imported this dataset (available <a href="https://github.com/OxCGRT/covid-policy-tracker/raw/master/data/OxCGRT_latest.csv" rel="nofollow noreferrer">here</a>) as a csv file into R:</p>
  <pre><code>oxcgrt &lt;- read_csv(&quot;C:/Users/Local/Documents/COVID19datasets/OxCGRT/OxCGRT_latest.csv&quot;)
  </code></pre>
  <blockquote>
  <p>Parsed with column specification: cols(   .default = col_double(),<br />
  CountryName = col_character(),   CountryCode = col_character(),<br />
  M1_Wildcard = col_logical() ) See spec(...) for full column
  specifications.</p>
  </blockquote>
  <p>I used <code>summarize()</code> on variable &quot;E1_Income support&quot;:</p>
  <pre><code>summarize(oxcgrt, inc_sup = mean(&quot;E1_Income support&quot;, na.rm = TRUE))
  </code></pre>
  <blockquote>
  <pre><code># A tibble: 1 x 1
    inc_sup
      &lt;dbl&gt;
  1      NA
  Warning message:
  In mean.default(&quot;E1_Income support&quot;, na.rm = TRUE) :
    argument is not numeric or logical: returning NA
  </code></pre>
  </blockquote>
  <p>The issue could not be NA values in the variable since I specified &quot;na.rm = TRUE&quot;. However another command does it:</p>
  <pre><code>mean(oxcgrt$&quot;E1_Income support&quot;, na.rm=TRUE)
  # [1] 0.4758057
  </code></pre>
  <p>Variable &quot;E1_Income support&quot; is not numeric:</p>
  <pre><code>is.numeric(&quot;E1_Income support&quot;)
  # [1] FALSE
  </code></pre>
  <p>Does anyone know why the latter can calculate the mean but not the former?
  Thank you</p>
  <p>P.S.: the data is updated daily, so variable mean should be slightly different from the mean I reported.</p>