document.write( "Question 328703: A drug is known to be 80% effective in curing a certain disease. If four people with the disease are to be given the drug, the probability that more than two will be cured is: \n" ); document.write( "

Algebra.Com's Answer #235478 by Edwin McCravy(20060) $\"\"$ $\"About$

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A drug is known to be 80% effective in curing a certain disease. If four people with the disease are to be given the drug, the probability that more than two will be cured is:
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document.write( "The binomial probability of exactly x successes in n independent trials, when\r\n" );
document.write( "the probability of exactly one success in one trial is p, is given by:\r\n" );
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document.write( "Here there are n trials so n = 4.  The probability of one success (cure) in 1\r\n" );
document.write( "trial is .8, so p=.8\r\n" );
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document.write( "\"More than two\" means \"three or four\", and \"or\" means to add, so\r\n" );
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document.write( "the probability of 3 or 4 being cured is\r\n" );
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document.write( ".8192\r\n" );
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document.write( "You can also find that in the binomial table in your book\r\n" );
document.write( "with n = 4 and p = .8\r\n" );
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document.write( "Or if you have a TI-83 or TI-84 calculator\r\n" );
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document.write( "On the calculator you have to consider the complement event as\r\n" );
document.write( "1 - probability that 2 or fewer will be cured:\r\n" );
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document.write( "Press ON\r\n" );
document.write( "Press CLEAR\r\n" );
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document.write( "Type 1-\r\n" );
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document.write( "Press 2ND\r\n" );
document.write( "Press VARS\r\n" );
document.write( "Press ALPHA\r\n" );
document.write( "Press APPS\r\n" );
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document.write( "You should see this -->    1-binomcdf(   \r\n" );
document.write( "followed by a blinking cursor.\r\n" );
document.write( "After the parenthesis type this -->  4,.8,2)\r\n" );
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document.write( "You should see this -->    1-binomcdf(4,.8,\r\n" );
document.write( "                           2)\r\n" );
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document.write( "Press ENTER\r\n" );
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document.write( "You should see the answer .8192\r\n" );
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document.write( "Edwin

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