title: Correlation Matrix with multiple binary variables
body: <p>I have a few dichotomous variables (around 15) that I want to correlate with each other.</p>
  <p>For the sake of simplicity, I will describe my problem using a similar, more simple data set.</p>
  <p>Let's assume we have a data frame containing 5 Variables</p>
  <pre><code>var1 &lt;- c(1,0,0,1,NA,1,0,0,1,NA)
  var2 &lt;- c(1,NA,1,1,NA,1,NA,1,1,NA)
  var3 &lt;- c(NA,0,0,1,NA,NA,0,0,1,NA)
  var4 &lt;- c(0,0,0,NA,1,0,0,0,NA,1)
  var5 &lt;- c(1,1,0,1,NA,1,1,0,1,NA)
  
  DF &lt;- data.frame(var1, var2, var3, var4, var5)
  
  </code></pre>
  <p>Since I only have binary variables, I cannot use a pearson correlation.</p>
  <p>I've read, that a chi square test or a phi correlation would fit my problem, but I've only found instructions with 2 variables resp. a 2x2 frame, not multiple variables.</p>
  <p>Is there a way to correlate several binary variables with one another and to represent them using a matrix?</p>
  <p>Thank you very much in advance for your answer!</p>