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   <h2 class="chapterHead"><span class="titlemark">Chapter&#x00A0;3</span><br /><a 
  name="x14-220003"></a>Basic Observations </h2>
<!--l. 591--><p class="noindent">The principle observable quantity is the empirical error rate (<!--l. 591--><math 
xmlns="http://www.w3.org/1998/Math/MathML" 
mode="inline">
<mrow 
><msub><mrow 
><mover 
accent="true"><mrow 
><mi 
>e</mi></mrow><mo 
class="MathClass-op">&#x0302;</mo></mover></mrow><mrow 
><mi 
>S</mi></mrow></msub 
><mrow><mo 
class="MathClass-open">(</mo><mrow><mi 
>h</mi></mrow><mo 
class="MathClass-close">)</mo></mrow></mrow></math>) of a
hypothesis. What is the distribution of the empirical error rate for a fixed hypothesis? For each
example, we know that the probability that the hypothesis will err is given by true error rate, <!--l. 594--><math 
xmlns="http://www.w3.org/1998/Math/MathML" 
mode="inline">
<mrow 
><msub><mrow 
><mi 
>e</mi></mrow><mrow 
><mi 
>D</mi></mrow></msub 
><mrow><mo 
class="MathClass-open">(</mo><mrow><mi 
>h</mi></mrow><mo 
class="MathClass-close">)</mo></mrow></mrow></math>. This
can be modeled by a biased coin flip: heads if you are wrong and tails if you are
right.
</p><!--l. 597--><p class="indent">   Let us call the bias of the coin <!--l. 597--><math 
xmlns="http://www.w3.org/1998/Math/MathML" 
mode="inline">      <mrow 
><mi 
>p</mi> <mo 
class="MathClass-rel">=</mo> <msub><mrow 
><mi 
>e</mi></mrow><mrow 
><mi 
>D</mi></mrow></msub 
><mrow><mo 
class="MathClass-open">(</mo><mrow><mi 
>h</mi></mrow><mo 
class="MathClass-close">)</mo></mrow></mrow></math>.
What then is the probability of observing <!--l. 598--><math 
xmlns="http://www.w3.org/1998/Math/MathML" 
mode="inline">
<mrow 
><mi 
>k</mi></mrow></math> heads out
of <!--l. 598--><math 
xmlns="http://www.w3.org/1998/Math/MathML" 
mode="inline">        <mrow 
><mi 
>m</mi></mrow></math>
coin flips? This is a very familiar distribution in statistics called the Binomial distribution. Let
<!--l. 599--><math 
xmlns="http://www.w3.org/1998/Math/MathML" 
mode="inline">     <mrow 
><mover 
accent="true"><mrow 
><mi 
>p</mi></mrow><mo 
class="MathClass-op">&#x0302;</mo></mover></mrow></math>
be the observed rate of heads.
</p>
   <div class="newtheorem">
<!--l. 602--><p class="noindent"><span class="head">
<a 
  name="x14-22001r1"></a>
  <span 
class="eccc-1000">D<small 
class="small-caps">E</small><small 
class="small-caps">F</small><small 
class="small-caps">I</small><small 
class="small-caps">N</small><small 
class="small-caps">I</small><small 
class="small-caps">T</small><small 
class="small-caps">I</small><small 
class="small-caps">O</small><small 
class="small-caps">N</small> </span>3.0.1<span 
class="eccc-1000">.</span></span>
</p><!--l. 603--><p class="indent">   (Binomial Distribution) The Binomial distribution is given by: <!--l. 604--><math 
xmlns="http://www.w3.org/1998/Math/MathML" 
mode="display">      <mrow 
>
                             <msub><mrow 
><mo 
>Pr</mo></mrow><mrow 
><msup><mrow 
><mrow><mo 
class="MathClass-open">{</mo><mrow><mn>0</mn><mo 
class="MathClass-punc">,</mo><mn>1</mn></mrow><mo 
class="MathClass-close">}</mo></mrow></mrow><mrow 
><mi 
>m</mi></mrow></msup 
></mrow></msub 
> <mfenced separators="" 
open="("  close=")" ><mrow><mover 
accent="true"><mrow 
><mi 
>p</mi></mrow><mo>&#x0302;</mo></mover> <mo 
class="MathClass-rel">=</mo>  <mfrac><mrow 
><mi 
>k</mi></mrow> 
<mrow 
><mi 
>m</mi></mrow></mfrac><mo 
class="MathClass-rel">&#x2223;</mo><mi 
>p</mi></mrow></mfenced> <mo 
class="MathClass-rel">=</mo><mfenced separators="" 
open="(" close=")"><mfrac linethickness="0.0pt"><mrow> <mi 
>m</mi></mrow> 
<mrow><mi 
>k</mi></mrow></mfrac></mfenced> <msup><mrow 
><mi 
>p</mi></mrow><mrow 
><mi 
>k</mi></mrow></msup 
><msup><mrow 
><mrow><mo 
class="MathClass-open">(</mo><mrow><mn>1</mn> <mo 
class="MathClass-bin">&#x2212;</mo> <mi 
>p</mi></mrow><mo 
class="MathClass-close">)</mo></mrow></mrow><mrow 
><mi 
>m</mi><mo 
class="MathClass-bin">&#x2212;</mo><mi 
>k</mi></mrow></msup 
>
</mrow></math>
Here we use &#x2019;choose&#x2019; notation defined by <!--l. 606--><math 
xmlns="http://www.w3.org/1998/Math/MathML" 
mode="inline">      <mrow 
><mfenced separators="" 
open="(" close=")"><mfrac linethickness="0.0pt"><mrow><mi 
>m</mi></mrow>
<mrow><mi 
>k</mi></mrow></mfrac></mfenced>  <mo 
class="MathClass-rel">=</mo>     <mfrac><mrow 
><mi 
>m</mi><mi 
>!</mi></mrow> 
<mrow 
><mrow><mo 
class="MathClass-open">(</mo><mrow><mi 
>m</mi><mo 
class="MathClass-bin">&#x2212;</mo><mi 
>k</mi></mrow><mo 
class="MathClass-close">)</mo></mrow><mi 
>!</mi><mi 
>k</mi><mi 
>!</mi></mrow></mfrac></mrow></math>.
</p>
   </div>
   <div class="sectionTOCS"><span class="sectionToc">&#x00A0;3.1.&#x00A0;&#x00A0;<a 
href="thesisse9.xml#x15-230003.1" name="QQ2-15-23">The Basic Building Block</a></span><br /><span class="sectionToc">&#x00A0;3.2.&#x00A0;&#x00A0;<a 
href="thesisse10.xml#x16-240003.2" name="QQ2-16-24">Approximation techniques</a></span><br /><span class="sectionToc">&#x00A0;3.3.&#x00A0;&#x00A0;<a 
href="thesisse11.xml#x17-250003.3" name="QQ2-17-25">Binomial
                                                                     

                                                                     
Tail calculation techniques</a></span><br /><span class="sectionToc">&#x00A0;3.4.&#x00A0;&#x00A0;<a 
href="thesisse12.xml#x18-260003.4" name="QQ2-18-26">Converting to a P-value approach</a></span><br /><span class="sectionToc">&#x00A0;3.5.&#x00A0;&#x00A0;<a 
href="thesisse13.xml#x19-270003.5" name="QQ2-19-28">Bounding
the Union</a></span><br /><span class="sectionToc">&#x00A0;3.6.&#x00A0;&#x00A0;<a 
href="thesisse14.xml#x20-280003.6" name="QQ2-20-29">Arbitrary Loss functions</a></span><br />
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