title: R model creation does not work
body: <p>I'm trying to build a prediction model in R, but no method works. 
  I read the data from a csv file to build a list:</p>
  
  <pre><code>data &lt;- read.table("data.csv",header=T,sep=";")
  </code></pre>
  
  <p>After that, I filter the data for training:</p>
  
  <pre><code>trainings &lt;- data [!is.na(data$isWorking),]
  </code></pre>
  
  <p>Then I use package rpart to create a decision tree</p>
  
  <pre><code>tree &lt;- rpart(isWorking ~ ., data=trainings)
  </code></pre>
  
  <p>Followed by make a prediction with the training data to evaluate it</p>
  
  <pre><code>prd &lt;- predict(tree, newdata=trainings)
  </code></pre>
  
  <p>Unfortunately I'm not getting 0 and 1 as result for my prediction. Other procedures like knn, randomforest, etc. also doesn't work.</p>
  
  <p>This is the result if I plot the prediction. Usually, it should be values 0 and 1.</p>
  
  <p><a href="https://i.stack.imgur.com/x61A5.png" rel="nofollow noreferrer">Plot of prediction</a></p>