reiver-artificial-intelligence/levels of measurement.html

<article>
	<h1>Levels of Measurement</h1>
	<section>
		<address class="h-card">
			by
			<a rel="author" class="u-url" href="http://changelog.ca/"><span class="p-given-name">Charles</span> <span class="p-additional-name">Iliya</span> <span class="p-family-name">Krempeaux</span></a>
		</address>
	</section>
	<section>
		<p>
			The <strong>levels of measurement</strong> are a way of categorizing a <ziba-link>data</ziba-link> as one of four different categories:
		</p>
		<ul>
			<li><ziba-link>nominal data</ziba-link>,</li>
			<li><ziba-link>ordinal data</ziba-link>,</li>
			<li><ziba-link>interval data</ziba-link>, and</li>
			<li><ziba-link>ratio data</ziba-link>.</li>
		</ul>
	</section>
	<section>
		<h2>Ratio Data</h2>
	</section>
	<section>
		<h2>Interval Data</h2>
	</section>
	<section>
		<h2>Ordinal Data</h2>
	</section>
	<section>
		<h2>Nominal Data</h2>
		<section>
			<p>
				An example of <strong>nominal data</strong> is <em>blood types</em>:
			</p>
			<ul>
				<li>type A+</li>
				<li>type A-</li>
				<li>type B+</li>
				<li>type B-</li>
				<li>type AB+</li>
				<li>type AB-</li>
				<li>type O+</li>
				<li>type O-</li>
			</ul>
		</section>
		<section>
			<p>
				Another example of <strong>nominal data</strong> is <em>sex</em>:
			</p>
			<ul>
				<li>female</li>
				<li>male</li>
			</ul>
		</section>
		<section>
			<p>
				Another example of <strong>nominal data</strong> is <em>family names</em>:
			</p>
			<ul>
				<li>Alves</li>
				<li>Beg</li>
				<li>Chen</li>
				<li>Cho</li>
				<li>Choi</li>
				<li>da Silva</li>
				<li>Dickson</li>
				<li>dos Santos</li>
				<li>Esfahani</li>
				<li>Fernández</li>
				<li>Ferreira</li>
				<li>García</li>
				<li>Jung</li>
				<li>Kang</li>
				<li>Kerr</li>
				<li>Kim</li>
				<li>Krempeaux</li>
				<li>Li</li>
				<li>Liu</li>
				<li>Martin</li>
				<li>Müller</li>
				<li>Pahlavi</li>
				<li>Park</li>
				<li>Parsi</li>
				<li>Pereira</li>
				<li>Rodríguez</li>
				<li>Safavi</li>
				<li>Sasani</li>
				<li>Wang</li>
				<li>Yun</li>
				<li>Zhang</li>
				<li><em>etc</em></li>
			</ul>
		</section>
		<section>
			<p>
				Another example of <strong>nominal data</strong> is <em>hair color</em>:
			</p>
			<ul>
				<li>brown</li>
				<li>black</li>
				<li>blond</li>
				<li>gray</li>
				<li>red</li>
				<li><em>etc</em></li>
			</ul>
		</section>
		<section>
			<p>
				Another example of <strong>nominal data</strong> is <em>cities</em>:
			</p>
			<ul>
				<li>Beijing</li>
				<li>Bangalore</li>
				<li>Bangkok</li>
				<li>Bogotá</li>
				<li>Buenos Aires</li>
				<li>Cairo</li>
				<li>Chennai</li>
				<li>Chicago</li>
				<li>Chongqing</li>
				<li>Dallas</li>
				<li>Delhi</li>
				<li>Dhaka</li>
				<li>Guangzhou</li>
				<li>Hyderabad</li>
				<li>Kinshasa</li>
				<li>Kolkata</li>
				<li>Isfahan</li>
				<li>Istanbul</li>
				<li>Jakarta</li>
				<li>Karachi</li>
				<li>Lagos</li>
				<li>Lahore</li>
				<li>Lima</li>
				<li>London</li>
				<li>Los Angeles</li>
				<li>Moscow</li>
				<li>Nagoya</li>
				<li>New York City</li>
				<li>Osaka</li>
				<li>Manila</li>
				<li>Mexico City</li>
				<li>Mumbai</li>
				<li>Paris</li>
				<li>Rio de Janeiro</li>
				<li>São Paulo</li>
				<li>Seoul</li>
				<li>Shanghai</li>
				<li>Shenzhen</li>
				<li>Tehran</li>
				<li>Tianjin</li>
				<li>Tokyo</li>
				<li>Toronto</li>
				<li>Vancouver</li>
				<li><em>etc</em></li>
			</ul>
		</section>
	</section>
	<section>
		<h2>Operations</h2>
		<p>
			One way of understanding the <strong>levels of measurement</strong> is — what type of <strong>operations</strong> are meaningful and valid for that type of data‽
		</p>
		<p>
			Here is a table that summarizes what <strong>operations</strong> are and are <em>not</em >meaningful and valid for each <strong>levels of measurement</strong> category:
		</p>
		<table>
			<thead>
				<tr>
					<th></th>
					<th>nominal</th>
					<th>ordinal</th>
					<th>interval</th>
					<th>ratio</th>
				</tr>
			</thead>
			<tbody>
				<tr>
					<td>can × and ÷ ?</td>
					<td>no</td>
					<td>no</td>
					<td>no</td>
					<td>YES</td>
				</tr>
				<tr>
					<td>can + and - ?</td>
					<td>no</td>
					<td>no</td>
					<td>YES</td>
					<td>YES</td>
				</tr>
				<tr>
					<td>can &lt; and &gt; ?</td>
					<td>no</td>
					<td>YES</td>
					<td>YES</td>
					<td>YES</td>
				</tr>
				<tr>
					<td>can = and ≠ ?</td>
					<td>YES</td>
					<td>YES</td>
					<td>YES</td>
					<td>YES</td>
				</tr>
			</tbody>
		</table>
	</section>
</article>