document.write( "Question 286508: An accounting professor claims that one quarter of undergraduate business students major in accounting. If we assume this is true, what is the probability that in a random sample of 790 undergraduate business students, 179 or more will major in accounting? \n" ); document.write( "

Algebra.Com's Answer #207823 by Edwin McCravy(20060) $\"\"$ $\"About$

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An accounting professor claims that one quarter of undergraduate business students major in accounting. If we assume this is true, what is the probability that in a random sample of 790 undergraduate business students, 179 or more will major in accounting?
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document.write( "If you have a TI-83 or 84 calculator,\r\n" );
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document.write( "Press CLEAR\r\n" );
document.write( "Type this:   1-\r\n" );
document.write( "Press 2nd\r\n" );
document.write( "Press VARS\r\n" );
document.write( "Press ALPHA\r\n" );
document.write( "Press APPS  \r\n" );
document.write( "You will see this:    1-binomcdf(\r\n" );
document.write( "Type this:            790,1/4,179)\r\n" );
document.write( "You will see this:    1-binomcdf(790,1/4,179)\r\n" );
document.write( "Press ENTER\r\n" );
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document.write( "You will see this:    .9315736737\r\n" );
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document.write( "If you don't have a calculator that will do this directly,\r\n" );
document.write( "you must use a NORMAL APPROXIMATION OF THE BINOMIAL:\r\n" );
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document.write( "Calculate the mean: \r\n" );
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document.write( "Calculate the standard deviation: \r\n" );
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document.write( "We want to find P(x > 179) Since the approximation \r\n" );
document.write( "is to include 179, and 179 is less than the mean, \r\n" );
document.write( "we want P(x > 179.5)\r\n" );
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document.write( "Calculate the z-score for 178.5\r\n" );
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document.write( "P(x > 179.5) translates to P(z > -1.478966454)\r\n" );
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document.write( "Round the absolute value of z to hundredths. That's 1.48\r\n" );
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document.write( "In the nomal table find 1.4 in the leftmost column.\r\n" );
document.write( "Find the hundredths digit 8 (0.08) at the top, then read\r\n" );
document.write( "0.4306 if you have the kind of table that reads from the\r\n" );
document.write( "middle. Then add .5 to that and get 0.9306.  (If you have\r\n" );
document.write( "the other kind of table you will read 0.9306 driectly by\r\n" );
document.write( "looking up 1.48).\r\n" );
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document.write( "The approximation using the normal table is 0.9306.\r\n" );
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document.write( "The reason you don't get the same answer is because\r\n" );
document.write( "the calculator is more accurate than to normal tables.\r\n" );
document.write( "But you will noticethat both answers are .93 when\r\n" );
document.write( "rounded to hundredths.\r\n" );
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document.write( "Edwin

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