document.write( "Question 1037910: Hello in need assistance with solving this question, i also want to know/see what steps im missing :\r
\n" ); document.write( "\n" ); document.write( "Given a population mean IQ =100 and a standard deviation of 16, for a random sample of size 64, what is the probability that the sample mean IQ will be greater than 104?
\n" ); document.write( "would be less than 96
\n" ); document.write( "would be less than 98\r
\n" ); document.write( "\n" ); document.write( "Im not sure if im doing my calculations right,
\n" ); document.write( "z=104-100\16=0.25 \n" ); document.write( "

Algebra.Com's Answer #652570 by Edwin McCravy(20056) $\"\"$ $\"About$

You can put this solution on YOUR website!
Hello in need assistance with solving this question, i also want to
\n" ); document.write( "know/see what steps im missing :\r
\n" ); document.write( "\n" ); document.write( "Given a population mean IQ =100 and a standard deviation of 16, for
\n" ); document.write( "a random sample of size 64, what is the probability that the sample
\n" ); document.write( "mean IQ
\n" ); document.write( "will be greater than 104?
\n" ); document.write( "would be less than 96
\n" ); document.write( "would be less than 98\r
\n" ); document.write( "\n" ); document.write( "I'm not sure if im doing my calculations right,
\n" ); document.write( "z=104-100\16=0.25
\n" ); document.write( "

\r\n" );
document.write( "You're getting two things mixed up.\r\n" );
document.write( "\r\n" );
document.write( "1.  When you are selecting just ONE THING at random and looking \r\n" );
document.write( "    for the probability that that ONE THING's VALUE is within a\r\n" );
document.write( "    certain range.\r\n" );
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document.write( "and \r\n" );
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document.write( "2. When you are selecting A WHOLE LOT OF THINGS at random and looking \r\n" );
document.write( "   for the probability that THEIR AVERAGE (MEAN) value is within a\r\n" );
document.write( "   certain range.\r\n" );
document.write( "\r\n" );
document.write( "This is case 2, not case 1.  When you select a whole lot of things, \r\n" );
document.write( "the whole lot of things is called \"a sample\" and the number of things \r\n" );
document.write( "in the sample is called the \"sample size\", n.\r\n" );
document.write( "\r\n" );
document.write( "In case 1 you're looking for a value of x. In case 2 you are looking\r\n" );
document.write( "for a value of x-bar, written this way: x\r\n" );
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document.write( "In case 1 you use this formula for z\r\n" );
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document.write( "    x - m\r\n" );
document.write( "z = 覧覧覧 \r\n" );
document.write( "      s\r\n" );
document.write( "\r\n" );
document.write( "In case 2 you use this formula for z\r\n" );
document.write( "\r\n" );
document.write( "    x - m\r\n" );
document.write( "z = 覧覧覧 \r\n" );
document.write( "      \r\n" );
document.write( "\r\n" );
document.write( "The big difference is that when you select many things (a sample) \r\n" );
document.write( "you must divide the standard deviation by the square root of the \r\n" );
document.write( "sample size.\r\n" );
document.write( "\r\n" );
document.write( "You must use the second formula in this problem because you have a sample:\r\n" );
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document.write( "\r\n" );
document.write( "    104 - 100\r\n" );
document.write( "z = 覧覧覧覧予r\n" );
document.write( "     \r\n" );
document.write( "\r\n" );
document.write( "Don't forget to divide the standard deviation by the square root\r\n" );
document.write( "of the sample size (the number of things in the sample).  If you\r\n" );
document.write( "need further help, tell me about it in the thank-you note form\r\n" );
document.write( "below, and I'll get back to you by email.  BTW, I don't charge any\r\n" );
document.write( "money.  I'm a retired math prof and do this as a hobby.\r\n" );
document.write( "\r\n" );
document.write( "Edwin

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