document.write( "Question 201221This question is from textbook statistics techniques in business and economics
\n" ); document.write( ": A normal population has a mean of 80.0 and a standard deviation of 14.0 \r
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Algebra.Com's Answer #151463 by Edwin McCravy(20055) $\"\"$ $\"About$

You can put this solution on YOUR website!
A normal population has a mean of 80.0 and a standard deviation of 14.0 \r
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document.write( "calculate z-score for lower bound \r\n" );
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document.write( "That rounds to -1.79\r\n" );
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document.write( "calculate z-score for upper bound \r\n" );
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document.write( "That rounds to -0.71\r\n" );
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document.write( "Now whichever way you go from here depends on what kind\r\n" );
document.write( "of table you have, or whether you use a calculator.\r\n" );
document.write( "Different books have different kinds of normal tables.  \r\n" );
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document.write( "If your normal table has negative values of z listed:\r\n" );
document.write( "    1.  Find -0.7 in the z column.\r\n" );
document.write( "    2.  Go across until you are under the .01 column\r\n" );
document.write( "    3.  Read 0.2389 as the area left of -0.7\r\n" );
document.write( "    4.  Find -1.7 in the z column.\r\n" );
document.write( "    5.  Go across until you are under the .09 column\r\n" );
document.write( "    6.  Read 0.0367 as the area left of -1.79  \r\n" );
document.write( "    7.  Subtract 0.2389-0.0367\r\n" );
document.write( "    8.  Get 0.2022\r\n" );
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document.write( "If your normal table does not have negative values of z\r\n" );
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document.write( "    1.  Find 0.7 in the z column.\r\n" );
document.write( "    2.  Go across until you are under the .01 column\r\n" );
document.write( "    3.  Read 0.2611 as the area between 0.5 and 0.71\r\n" );
document.write( "    4.  Find 1.7 in the z column.\r\n" );
document.write( "    5.  Go across until you are under the .09 column\r\n" );
document.write( "    6.  Read 0.4633 as the area between 0.5 and 1.79  \r\n" );
document.write( "    7.  Subtract 0.4633-0.2611\r\n" );
document.write( "    8.  Get 0.2022 \r\n" );
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document.write( "Either way the probability is 0.2022.  However, this is only \r\n" );
document.write( "accurate to two decimal places, since 0.71 was only accurate\r\n" );
document.write( "to two decimal places, so we should round off to 0.20.\r\n" );
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document.write( "If you have a TI-84 calculator:\r\n" );
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document.write( "Clear the calculator and get on the main screen\r\n" );
document.write( "Press 2nd\r\n" );
document.write( "Press VARS\r\n" );
document.write( "Press 2\r\n" );
document.write( "You should see normalcdf(\r\n" );
document.write( "after that parentheses type this 55.0,70.0,80.0,14.0)\r\n" );
document.write( "You should see normalcdf(55.0,70.0,80.0,14.0)\r\n" );
document.write( "Press ENTER\r\n" );
document.write( "Read 0.2004524729\r\n" );
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document.write( "The calculator is much more accurate than the table.\r\n" );
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document.write( "Edwin

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