title: Error in boxplot, argument "x" is missing, with no default
body: <p>I'm trying to make a boxplot in R markdown with two variables (named "suicides/100k pop" and "sex" in the .xlsx file, with "sex" being nominal with options male/female) but it's not producing the plot.</p>
  
  <blockquote>
    <p></p>
  </blockquote>
  
  <pre><code>suicidedata = as.data.frame(readxl::read_xlsx(
    path = "(...)\suicidedata.xlsx",
  ))
  </code></pre>
  
  <pre><code>boxplot(
    formula = "suicides/100k pop" ~ "sex",
  )
  </code></pre>
  
  <p>The error: </p>
  
  <blockquote>
    <p>Error in boxplot.default(formula ="suicides/100k pop" ~ "sex", : argument "x" is missing, with no default calls:  ... withVisible -> eval -> eval -> boxplot -> boxplot.default Execution </p>
  </blockquote>
  
  <p>What do I do to make it print the boxplot?</p>