title: R: How to plot a boxplot with numeric x-axis for according spacing (not ggplot)
body: <p>I want to plot a boxplot with the regular /boxplot function of R  - not ggplot.
  Y and X axis are continously numeric varibales (x-axis 6 forces: 1.0, 1.3, 1.6, 2.0, 2.5, 3.1 [N])
  On Y-axis the participants ratings (1 to 7).</p>
  <p>I would like to plot it, with quantified spacing on x-axis, and also later add regression line into the plot. Cant find anything for the regular /boxplot function.</p>
  <p>Code so far:</p>
  <pre class="lang-r prettyprint-override"><code>kraft_ou &lt;- data.frame(VR1_100$ou_kraft, 
                         VR1_125$ou_kraft, 
                         VR1_160$ou_kraft, 
                         VR1_200$ou_kraft, 
                         VR1_250$ou_kraft, 
                         VR1_310$ou_kraft)
  colnames(kraft_ou) &lt;- c(&quot;kraft_100&quot;, &quot;kraft_125&quot;, &quot;kraft_160&quot;, &quot;kraft_200&quot;, &quot;kraft_250&quot;, &quot;kraft_310&quot;)
  kraft_ou
  
  boxplot(kraft_ou,
          names=c(&quot;1,0 [N]&quot;, &quot;1,3 [N]&quot;,&quot;1,6 [N]&quot;,&quot;2,0 [N]&quot;,&quot;2,5 [N]&quot;,&quot;3,1 [N]&quot;), 
          col = &quot;bisque&quot;,
          ylim = c(1, 7))
  points(1:6, meanskraftou, pch=4)
  text(1:6, meanskraftou + 0.24, labels = meanskraftou)
  abline(h=4)
  </code></pre>
  <p>data (n=30 ratings from 1 to 7 for each of the 6 forces):</p>
  <blockquote>
  <p>dput(kraft_ou)
  structure(list(kraft_100 = c(4, 3, 5, 5, 3, 4, 2, 4, 4, 5, 4,
  5, 5, 4, 4, 3, 4, 4, 5, 4, 6, 5, 4, 5, 5, 5, 4, 4, 4, 4), kraft_125 = c(4,
  4, 5, 6, 4, 3, 4, 4, 4, 5, 4, 5, 4, 5, 4, 3, 4, 4, 4, 6, 6, 4,
  4, 5, 3, 5, 4, 4, 4, 5), kraft_160 = c(5, 6, 6, 6, 6, 4, 6, 5,
  6, 5, 4, 3, 6, 6, 6, 5, 5, 5, 5, 6, 6, 6, 5, 5, 4, 6, 4, 5, 5,
  5), kraft_200 = c(6, 5, 6, 6, 5, 4, 5, 5, 6, 7, 5, 3, 5, 5, 5,
  4, 7, 6, 5, 5, 7, 6, 5, 6, 6, 6, 5, 4, 5, 3), kraft_250 = c(5,
  6, 6, 7, 6, 6, 6, 6, 7, 7, 6, 5, 7, 7, 5, 5, 6, 6, 7, 7, 6, 6,
  5, 5, 5, 7, 4, 6, 6, 5), kraft_310 = c(7, 7, 7, 7, 6, 5, 6, 6,
  6, 7, 4, 5, 7, 6, 5, 5, 7, 6, 5, 6, 6, 6, 5, 6, 5, 6, 5, 6, 6,
  6)), class = &quot;data.frame&quot;, row.names = c(NA, -30L))</p>
  </blockquote>