title: predicting outcome with a model in R
body: <p>I am trying to do a simple prediction, using linear regression
  I have a data.frame where some of the items are missing price (and therefor noted NA).
  This apperantely doesn't work:</p>
  
  <pre><code>#Simple LR
  fit &lt;- lm(Price ~ Par1 + Par2 + Par3, data=combi[!is.na(combi$Price),])
  Prediction &lt;- predict(fit,  data=combi[is.na(combi$Price),]), OOB=TRUE, type = "response")
  </code></pre>
  
  <p>What should I put instead of <code>data=combi[is.na(combi$Price),])</code> ?</p>