title: Error using Levene test in R after a group by [error: is not a numeric variable]
body: <p>I´m trying to use levene Test from "car" library in R with the iris dataset.</p>
  
  <p>The code I have is:</p>
  
  <pre><code>library(tidyverse)
  library(car)
  iris %&gt;% group_by (Species) %&gt;% leveneTest( Sepal.Length )
  </code></pre>
  
  <p>From there I´m getting the following error:</p>
  
  <pre><code>Error in leveneTest.default(., Sepal.Length) : 
    . is not a numeric variable
  </code></pre>
  
  <p>I don´t know how to fix this, since the data types seem to be of the rigth type:</p>
  
  <pre><code>&gt; str(iris)
  'data.frame':   150 obs. of  5 variables:
   <span class="math-container">$ Sepal.Length: num  5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
   $</span> Sepal.Width : num  3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
   <span class="math-container">$ Petal.Length: num  1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
   $</span> Petal.Width : num  0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
   $ Species     : Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...
  </code></pre>