document.write( "Question 414381: It is estimated that an average of 53% of college students graduate in 5 years or less. If 500 students on a large campus are selected at random, what is the probability that between 50% and 60% of them will graduate in 5 years or less? \n" ); document.write( "

Algebra.Com's Answer #290694 by Edwin McCravy(20060) $\"\"$ $\"About$

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It is estimated that an average of 53% of college students graduate in 5 years or less. If 500 students on a large campus are selected at random, what is the probability that between 50% and 60% of them will graduate in 5 years or less?
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document.write( "This is a binomial problem with\r\n" );
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document.write( "You are asked:\r\n" );
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document.write( "What is the probability that between 50% and 60% of them \r\n" );
document.write( "will graduate in 5 years or less?\r\n" );
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document.write( "Since 50% of 500 is 250 and 69% of 500 is 300, this is the\r\n" );
document.write( "same as being asked\r\n" );
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document.write( "What is the probability that between 250 and 300 of the 500 \r\n" );
document.write( "will graduate in 5 years or less?\r\n" );
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document.write( "You can do this on a TI-83 or TI-84 by\r\n" );
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document.write( "binomcdf(500,.53,300) - binomcdf(500,.53,250)\r\n" );
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document.write( "getting .902291559.\r\n" );
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document.write( "Or you can do it by approximating the binomial with the normal.\r\n" );
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document.write( "normalcdf(249.5,300.5,265,11.16019713)\r\n" );
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document.write( "getting .916828909\r\n" );
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document.write( "Or if your teach won't let you use a calculator and insists on\r\n" );
document.write( "less accurate tables, then find the z-scores of\r\n" );
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document.write( "249.5 and 300.5,\r\n" );
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document.write( "and, depending on what kind of table you have, you will\r\n" );
document.write( "either \r\n" );
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document.write( "1. If your table has only positive z-scores,\r\n" );
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document.write( "look up 1.38, finding .4162, look up 3.18, finding .4993,\r\n" );
document.write( "add these and get .9155\r\n" );
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document.write( "or \r\n" );
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document.write( "2. If your table has both positive and negative z-scores,\r\n" );
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document.write( "look up -1.38, finding .0838, look up 3.18, finding .9993,\r\n" );
document.write( "subtract these and get .9155.\r\n" );
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document.write( "Edwin

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