al</dt><dd><p>Total number of incidents</p>
</dd>
</dl>



<h3>Source</h3>

<p>Presidential Commission on the Space Shuttle Challenger Accident, 
Vol. 1, 1986: 129-131.  
</p>


<h3>References</h3>

<p>Tufte, E. R. 1997. Visual Explanations. Graphics Press, Cheshire,
Connecticut, U.S.A.
</p>


<h3>Examples</h3>

<pre><code class='language-R'>oldpar &lt;- par(mfrow=c(1,2))
plot(Total~Temperature, data = orings[c(1,2,4,11,13,18),]) # the 
               # observations included in the pre-launch charts
plot(To