title: Setting the confidence interval in acf plots
body: <p>I plotted the <strong><em>autocorrelation function</em></strong> of a given set of residuals I obtained from estimating a linear regression model:</p>
  
  <pre><code>&gt; require("stats")
  &gt; acf(Reg$residuals)
  </code></pre>
  
  <p>It resulted in the following graphic: </p>
  
  <p><img src="https://i.stack.imgur.com/GoszB.png" alt="acf plot"></p>
  
  <p>I then wanted to look up what kind of confidence interval (95%, 99%) is displayed, but there is no information on that within the help section of the function. In addition to that I could not find a way to adjust the confidence interval manually. </p>
  
  <p>Is there a way to manually set the confidence interval displayed?</p>