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<document xmlns="http://cnx.rice.edu/cnxml" xmlns:md="http://cnx.rice.edu/mdml/0.4" xmlns:bib="http://bibtexml.sf.net/" xmlns:m="http://www.w3.org/1998/Math/MathML" id="new">
	<name>What is the probability of an even throw on a die?</name>
	<metadata>
  <md:version>1.4</md:version>
  <md:created>2006/03/03 12:41:16 US/Central</md:created>
  <md:revised>2006/03/05 02:16:49.291 US/Central</md:revised>
  <md:authorlist>
      <md:author id="Arnold_Mwesigye">
      <md:firstname>Arnold</md:firstname>
      
      <md:surname>Mwesigye</md:surname>
      <md:email>amwesiga@gmail.com</md:email>
    </md:author>
  </md:authorlist>

  <md:maintainerlist>
    <md:maintainer id="Arnold_Mwesigye">
      <md:firstname>Arnold</md:firstname>
      
      <md:surname>Mwesigye</md:surname>
      <md:email>amwesiga@gmail.com</md:email>
    </md:maintainer>
  </md:maintainerlist>
  
  

  <md:abstract/>
</metadata>
	<content>
		<para id="delete_me">The word probability is used to express uncertain <link src="http://cnx.org/content/m13476/latest/">events</link> or knowledge, being closely related in meaning to <emphasis>likely</emphasis>, <emphasis>risky</emphasis>, <emphasis>hazardous</emphasis>, and <emphasis>doubtful</emphasis>. <emphasis>Chance</emphasis>,<emphasis>odds</emphasis>, and <emphasis>bet</emphasis> are other words expressing similar notions. </para><para id="element-604">Probabilities are also thought of as numbers in a closed interval from 0 to 1 assigned to <link src="http://cnx.org/content/m13476/latest/">"events"</link> whose occurrence or failure to occur is random. </para><para id="element-661">The probability <emphasis>P</emphasis> of some <link src="http://cnx.org/GroupWorkspaces/wg412/module.2006-03-03.3712088375/module_text/">event</link>
			<emphasis>E </emphasis>, denoted <emphasis>P(E)</emphasis>, is defined with respect to a <link src="http://cnx.org/content/m13483/latest/">sample space</link> of all possible elementary events. </para><para id="element-375">Probability <emphasis>P(A)</emphasis>, assigned to an <link src="http://cnx.org/content/m13476/latest/">event</link>
			<emphasis>A</emphasis>, is defined as the number of possible occurrences in <emphasis>A</emphasis>, as a ratio of the sample space.</para><para id="element-70">Therefore; </para><para id="element-385"><emphasis>P(A) = N(A) / N(S)</emphasis></para><para id="element-183">To determine the probability of an occurrence we need to define it with respect to a <link src="http://cnx.org/content/m13483/latest/">sample space</link> of all possible elementary events. 


</para><para id="element-424"><term>Example:</term>
		</para><para id="element-237">If we define the <term>probability of an even throw</term> as the <link src="http://cnx.org/content/m13476/latest/">event</link>, <emphasis>E</emphasis>, then;
</para><para id="element-374"><emphasis>E = { 2, 4, 6 }</emphasis></para><para id="element-927">If we define the <link src="http://cnx.org/content/m13483/latest/">sample space</link>, <emphasis>S</emphasis>, as the total number of possible throws, then; </para><para id="element-330"><emphasis>S = {1, 2, 3, 4, 5, 6}</emphasis>. </para><para id="element-998">The <term>probability of an even throw on a die</term> is;    </para><para id="element-847"><emphasis>P(E) = P(E) / P(S)</emphasis></para><para id="element-925"><emphasis>P(E)</emphasis> = Number of even throws / Total number of possible throws</para><para id="element-444"><emphasis>P(E)</emphasis> = 3/6 = 1/2. </para><para id="element-844"><term>Exercise:</term></para><para id="element-867">In a single throw of a die, what is the probability of getting a number greater than four? <link src="http://cnx.org/content/m13485/latest/">Answer.</link></para><para id="element-583"><term>References:</term></para><para id="element-534">Wikipedia. "Statistical Independence", Wikipedia Foundation Inc, <link src="http://en.wikipedia.org/wiki/probability">"http://en.wikipedia.org/wiki/Probability"</link>, Last accessed 17th February 2006.</para><para id="element-146">Arnold Mwesigye</para><para id="element-215">Petrina Mangala</para>
	</content>
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