<p style="text-align:justify"><span style="font-size:14px"><span style="color:black">One simple graph, the&nbsp;<strong>stem-and-leaf graph</strong>&nbsp;or&nbsp;<strong>stemplot</strong>, comes from the field of exploratory data analysis. It is a good choice when the data sets are small. To create the plot, divide each observation of data into a stem and a leaf. The leaf consists of a&nbsp;<strong>final significant digit</strong>. For example, 23 has stem two and leaf three. The number 432 has stem 43 and leaf two. Likewise, the number 5,432 has stem 543 and leaf two. The decimal 9.3 has stem nine and leaf three. Write the stems in a vertical line from smallest to largest. Draw a vertical line to the right of the stems. Then write the leaves in increasing order next to their corresponding stem.</span></span></p>

<p style="text-align:justify">&nbsp;</p>

<p><span style="font-size:14px"><span style="color:#000000"><strong>EXAMPLE&nbsp;2.1</strong></span></span></p>

<p>&nbsp;</p>

<p><span style="font-size:14px"><span style="color:black">For Susan Dean&#39;s spring pre-calculus class, scores for the first exam were as follows (smallest to largest): 33; 42; 49; 49; 53; 55; 55; 61; 63; 67; 68; 68; 69; 69; 72; 73; 74; 78; 80; 83; 88; 88; 88; 90; 92; 94; 94; 94; 94; 96; 100</span></span></p>

<p style="text-align:justify">&nbsp;</p>

<table border="1" cellspacing="0" style="width:900px">
	<caption>
	<p><span style="font-size:20px"><strong>Table2.1 Stem-and-Leaf Graph</strong></span></p>
	</caption>
	<thead>
		<tr>
			<td>
			<div style="text-align:center"><span style="font-size:28px"><strong>Stem</strong></span></div>
			</td>
			<td>
			<div style="text-align:center"><span style="font-size:28px"><strong>Leaf</strong></span></div>
			</td>
		</tr>
	</thead>
	<tbody>
		<tr>
			<td>
			<div style="text-align:center"><span style="font-size:28px">3</span></div>
			</td>
			<td>
			<div style="text-align:center"><span style="font-size:28px">3</span></div>
			</td>
		</tr>
		<tr>
			<td>
			<div style="text-align:center"><span style="font-size:28px">4</span></div>
			</td>
			<td>
			<div style="text-align:center"><span style="font-size:28px">2 9 9</span></div>
			</td>
		</tr>
		<tr>
			<td>
			<div style="text-align:center"><span style="font-size:28px">5</span></div>
			</td>
			<td>
			<div style="text-align:center"><span style="font-size:28px">3 5 5</span></div>
			</td>
		</tr>
		<tr>
			<td>
			<div style="text-align:center"><span style="font-size:28px">6</span></div>
			</td>
			<td>
			<div style="text-align:center"><span style="font-size:28px">1 3 7 8 8 9 9</span></div>
			</td>
		</tr>
		<tr>
			<td>
			<div style="text-align:center"><span style="font-size:28px">7</span></div>
			</td>
			<td>
			<div style="text-align:center"><span style="font-size:28px">2 3 4 8</span></div>
			</td>
		</tr>
		<tr>
			<td>
			<div style="text-align:center"><span style="font-size:28px">8</span></div>
			</td>
			<td>
			<div style="text-align:center"><span style="font-size:28px">0 3 8 8 8</span></div>
			</td>
		</tr>
		<tr>
			<td>
			<div style="text-align:center"><span style="font-size:28px">9</span></div>
			</td>
			<td>
			<div style="text-align:center"><span style="font-size:28px">0 2 4 4 4 4 6</span></div>
			</td>
		</tr>
		<tr>
			<td>
			<div style="text-align:center"><span style="font-size:28px">10</span></div>
			</td>
			<td>
			<div style="text-align:center"><span style="font-size:28px">0</span></div>
			</td>
		</tr>
	</tbody>
</table>

<p>&nbsp;</p>

<p style="text-align:justify"><span style="font-size:14px"><span style="color:black">The stemplot shows that most scores fell in the 60s, 70s, 80s, and 90s. Eight out of the 31 scores or approximately 26%&nbsp;(831)(831)&nbsp;were in the 90s or 100, a fairly high number of As.</span></span></p>

<p style="text-align:justify">&nbsp;</p>

<p style="text-align:justify"><span style="font-size:14px"><span style="color:black">The stemplot is a quick way to graph data and gives an exact picture of the data. You want to look for an overall pattern and any outliers. An&nbsp;outlier&nbsp;is an observation of data that does not fit the rest of the data. It is sometimes called an&nbsp;extreme<strong> value.</strong>&nbsp;When you graph an outlier, it will appear not to fit the pattern of the graph. Some outliers are due to mistakes (for example, writing down 50 instead of 500) while others may indicate that something unusual is happening. It takes some background information to explain outliers, so we will cover them in more detail later</span><span style="color:#424242">.</span></span></p>