title: Plotting fitted linear regression that is multiplied by a factor of k
body: <p>Plotting a simple linear regression has the code</p>
  <pre><code>plot(X,Y, pch=16)
  </code></pre>
  <p>where Y_i=b_0 + b_1X_i and the fitted line is</p>
  <pre><code>abline(lm(Y~X))
  </code></pre>
  <p>Then what would the code be for the fitted value Y_hat if X is multiplied by a factor of k?
  Would it be</p>
  <pre><code>abline(k*lm(Y~X))
  </code></pre>
  <p>since k * Y_hat = k * b_0 + k * b_1 * X_i?</p>