document.write( "Question 1201897: What are the chances that a person who is murdered actually knew the murdered? The answer to this question explains why a lot of police detective work begins with relatives and friends of the victim. About 64% of people who are murdered actually knew the person who committed the murder. Suppose that a detective has 63 current unsolved murders.
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Algebra.Com's Answer #836573 by ikleyn(52778) $\"\"$ $\"About$

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\n" ); document.write( "What are the chances that a person who is murdered actually knew the murdered?
\n" ); document.write( "The answer to this question explains why a lot of police detective work begins
\n" ); document.write( "with relatives and friends of the victim. About 64% of people who are murdered
\n" ); document.write( "actually knew the person who committed the murder. Suppose that a detective has
\n" ); document.write( "63 current unsolved murders.
\n" ); document.write( "What is the probability that at least 35 of the victims knew their murderers?
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document.write( "The original problem is, of cource, a binomial distribution type.\r\n" );
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document.write( "But the number of trials is great: 63.\r\n" );
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document.write( "In such cases, the traditional approach is not to use the binopmial distribution formula.\r\n" );
document.write( "The traditional approach is to use the normal distribution as an approximation\r\n" );
document.write( "to the binomial distribution.\r\n" );
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document.write( "This normal distribution has the mean value n*p = 63*0.64 = 40.32 and the \r\n" );
document.write( "standard deviation  =  = 3.80988 (rounded).\r\n" );
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document.write( "With it, our goal is to find the area under this normal curve on the right of the \r\n" );
document.write( "raw mark 35;  more precisely, taking the continuity correction factor, on the right\r\n" );
document.write( "of the raw mark 34.5.  You can use regular calculator TI-83 or TI-84\r\n" );
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document.write( "                   z1    z2    mean    SD      <<<---===  formatting pattern\r\n" );
document.write( "    P = normalcdf(34.5, 9999, 40.32, 3.80988).\r\n" );
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document.write( "You get the ANSWER  0.9367.\r\n" );
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\n" ); document.write( "\n" ); document.write( "Solved.\r
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\n" ); document.write( "\n" ); document.write( "So, doing this way, you can solve the problem using the traditional tools and methods
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