title: Remove Control Limits With qcc Package in R (Quality Control Charts)
body: <p>I need to remove the lower control limit and center line (and their labels) from my control chart.</p>
  
  <p>Here's the code:</p>
  
  <pre><code># install.packages('qcc')
  library(qcc)
  nonconforming &lt;- c(3, 4, 6, 5, 2, 8, 9, 4, 2, 6, 4, 8, 0, 7, 20, 6, 1, 5, 7)
  samplesize &lt;- rep(50, 19)
  control &lt;- qcc(nonconforming, type = "p", samplesize, plot = "FALSE")
  warn.limits &lt;- limits.p(control$center, control$std.dev, control$sizes, 2)
  par(mar = c(5, 3, 1, 3), bg = "blue")
  plot(control, restore.par = FALSE, title = "P Chart for Medical Insurance Claims", 
       xlab = "Day", ylab = "Proportion Defective")
  abline(h = warn.limits, lty = 3, col = "blue")
  v2 &lt;- c("LWL", "UWL")  # the labels for warn.limits
  mtext(side = 4, text = v2, at = warn.limits, col = "blue", las = 2) 
  </code></pre>