title: New predictions in polynomial regression
body: <p>I got the following regression model and I am trying to do some predictions, but I always get an error:</p>
  
  <pre><code>model1 &lt;- lm(Sepal.Length ~ Petal.Length +  poly(Sepal.Width, 2), data = iris)
  predict(model1, model1$model)
  </code></pre>
  
  <blockquote>
    <p>Error in poly(Sepal.Width, 2, coefs = list(alpha = c(3.05733333333333,
    :  object 'Sepal.Width' not found</p>
  </blockquote>
  
  <p>I know I could simply access the fitted values for the predictions. 
  But let's say my new data looks like this:</p>
  
  <pre><code>newdata &lt;- head(model1$model) + 1
  </code></pre>
  
  <p>How can I do predictions on this new data set, without getting this error?</p>