Algebra.Com's Answer #833661 by ikleyn(52776)![\"\"](\"/images/stars/stars-13.gif\")  
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document.write( "Problem B:
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document.write( "The incubation time for chicks is normally distributed with a mean of 21 days,
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document.write( "and a standard deviation of approximately 1.2 days
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document.write( "(based on the information from the World Bank Encyclopedia).
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document.write( "If 1000 eggs are being incubated, how many chicks do we expect will hatch
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document.write( "(c) In 18.3 days or fewer?
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document.write( "(d) In at least 22.8 days?
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document.write( "(c) A normal distribution curve is a bell shaped curve.\r\n" );
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document.write( " The total area under each such curve is 1.\r\n" );
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document.write( " Of the 1000 eggs, the number of chicks that are expected to hatch, \r\n" );
document.write( " in part (c) make a ratio, which is the area under this specified normal curve\r\n" );
document.write( " on the  of the raw mark z= 18.3 days.\r\n" );
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document.write( " THEREFORE, our first step is to calculate the area under given normal curve\r\n" );
document.write( " on the left of the raw mark z = 18.3 days.\r\n" );
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document.write( " You can do it using the normal cumulative distribution function mormalcdf.\r\n" );
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document.write( " z1 z2 mu SD <<<---=== formatting\r\n" );
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document.write( " In your calculator it is p = normalcdf(-9999, 18.3, 21, 1.2) = 0.0122.\r\n" );
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document.write( " After getting this number p = 0.0122 (the probability, or the area under the curve), \r\n" );
document.write( " you multiply 1000 by p, and you get the desired ANSWER\r\n" );
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document.write( " | the number of chicks that are expected to hatch is 1000*0.0122 = 12.2, |\r\n" );
document.write( " | which we round to the closest integer number 12. |\r\n" );
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document.write( "(d) Similarly, in part (d), our first step is to calculate the area under given normal curve\r\n" );
document.write( " on the  of the raw mark z = 22.8 days.\r\n" );
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document.write( " You can do it using the normal cumulative distribution function mormalcdf.\r\n" );
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document.write( " z1 z2 mu SD <<<---=== formatting\r\n" );
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document.write( " In your calculator it is p = normalcdf(22.8, 9999, 21, 1.2) = 0.0668.\r\n" );
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document.write( " After getting this number p = 0.0668 (the probability, or the area under the curve), \r\n" );
document.write( " you multiply 1000 by p, and you get the desired ANSWER\r\n" );
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document.write( " | the number of chicks that are expected to hatch is 1000*0.0668 = 66.8, |\r\n" );
document.write( " | which we round to the closest integer number 67. |\r\n" );
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document.write( "Solved.\r
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