document.write( "Question 525398: I am having a hard time understanding standard normal distribution: \r
\n" ); document.write( "\n" ); document.write( "how would you figure this from a problem such as:\r
\n" ); document.write( "\n" ); document.write( "P(1.22 < Z < 2.15) \n" ); document.write( "
Algebra.Com's Answer #348108 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "You want to know what decimal fraction the green area\r\n" );
document.write( "is of the whole area on the normal curve.\r\n" );
document.write( "\r\n" );
document.write( "Notice it starts at z=1.22 on the z-axis and goes to z=2.15.\r\n" );
document.write( "\r\n" );
document.write( "On a TI-83 or 84 calculator you can find it by\r\n" );
document.write( "\r\n" );
document.write( "normalcdf(1.22,2.15).  You get .0954549502\r\n" );
document.write( "\r\n" );
document.write( "On a normal table you look up \r\n" );
document.write( "\r\n" );
document.write( "z = 2.15 and find either .4842 or .9842, depending on what\r\n" );
document.write( "kind of z-table you have.\r\n" );
document.write( "\r\n" );
document.write( "Then you look up \r\n" );
document.write( "\r\n" );
document.write( "z = 1.22 and find either .3888 or .8888, depending on what\r\n" );
document.write( "kind of z-table you have.\r\n" );
document.write( "\r\n" );
document.write( "Then you subtract the two values\r\n" );
document.write( "\r\n" );
document.write( ".4842-.3888 or .9842-.8888\r\n" );
document.write( "\r\n" );
document.write( "and you'll get .0954\r\n" );
document.write( "\r\n" );
document.write( "That's the fraction of the total area which the green\r\n" );
document.write( "area is of the entire area.  As a percent the green area\r\n" );
document.write( "is 9.54% of the total area between the z-axis and the normal\r\n" );
document.write( "curve.\r\n" );
document.write( "\r\n" );
document.write( "Edwin
\r
\n" ); document.write( "\n" ); document.write( "Edwin
\n" ); document.write( " \n" ); document.write( "
\n" );