37 lines
2.4 KiB
HTML
37 lines
2.4 KiB
HTML
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<article class="definition definition-like"><h2 class="heading">
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<span class="type">Definition</span><span class="space heading-divison-mark heading-divison-mark__space"> </span><span class="codenumber">3.1.1</span><span class="period heading-divison-mark heading-divison-mark__period">.</span>
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</h2>
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<div class="para logical">
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<div class="para">Let <span class="process-math">\(X\)</span> be a discrete random variable taking the values <span class="process-math">\(x_1, x_2, \dotsc, x_n\text{.}\)</span> The <dfn class="terminology">expected value</dfn> (also called <dfn class="terminology">mean</dfn>, or <dfn class="terminology">expectation</dfn>) of <span class="process-math">\(X\)</span> is the weighted average of the values of <span class="process-math">\(X\text{,}\)</span> where the weights are the probabilities of <span class="process-math">\(X\)</span> taking each value:</div>
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<div class="displaymath process-math">
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\begin{gather*}
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\E(X) = \sum_{i=1}^n x_i \Pr(X = x_i).
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\end{gather*}
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<div class="autopermalink" aria-hidden="true" data-description="Paragraph"><a tabindex="-1" href="#def-discrete-EV-1-1" title="Copy heading and permalink for Paragraph" aria-label="Copy heading and permalink for Paragraph">🔗</a></div>
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<div class="autopermalink" aria-hidden="true" data-description="Definition 3.1.1"><a tabindex="-1" href="#def-discrete-EV" title="Copy heading and permalink for Definition 3.1.1" aria-label="Copy heading and permalink for Definition 3.1.1">🔗</a></div>
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</article><span class="incontext"><a class="internal" href="sec-Expected-Value.html#def-discrete-EV">In Context</a></span>
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