document.write( "Question 811841: How many trials were conducted in a binomial distribution which has a mean of 8 and standard deviation of 2?
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Algebra.Com's Answer #488943 by Edwin McCravy(20055) $\"\"$ $\"About$

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Question 811841
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document.write( "mean = n·p\r\n" );
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document.write( "standard deviation = √n·p·(1-p)\r\n" );
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document.write( "n·p = 8\r\n" );
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document.write( "√n·p·(1-p) = 2\r\n" );
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document.write( "Square both sides of the second equation:\r\n" );
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document.write( "(√n·p·(1-p))² = (2)²\r\n" );
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document.write( "n·p(1-p) = 4\r\n" );
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document.write( "Substitute 8 for n·p\r\n" );
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document.write( "8(1-p) = 4\r\n" );
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document.write( "8-8p = 4\r\n" );
document.write( " -8p = -4\r\n" );
document.write( "   p = 0.5\r\n" );
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document.write( "    n·p = 8\r\n" );
document.write( "n·(0.5) = 8\r\n" );
document.write( "      n = \r\n" );
document.write( "      n = 16\r\n" );
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document.write( "Edwin

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