document.write( "Question 1191900: on an examination the average grade was 74 and standard deviation was 7 if 10% of the class are given A's and the distribution of grades is to follow a normal distribution then the lowest possible A and highest possible B if z10=1.28 is? \n" ); document.write( "
Algebra.Com's Answer #823747 by math_tutor2020(3817)\"\" \"About 
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\n" ); document.write( "mu = population mean of the class scores = 74
\n" ); document.write( "sigma = population standard deviation of the class scores = 7\r
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\n" ); document.write( "\n" ); document.write( "z10=1.28 indicates the z score for the top 10 percent\r
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\n" ); document.write( "\n" ); document.write( "This means P(Z > 1.28) = 0.10 approximately\r
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\n" ); document.write( "\n" ); document.write( "Let's find the raw score x based on this z score
\n" ); document.write( "z = (x-mu)/sigma
\n" ); document.write( "x-mu = z*sigma
\n" ); document.write( "x = mu+z*sigma
\n" ); document.write( "x = 74+1.28*7
\n" ); document.write( "x = 82.96\r
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\n" ); document.write( "\n" ); document.write( "The cut off between the highest B and the lowest A is an 82.96
\n" ); document.write( "If your teacher is rounding things to the nearest whole number, then it would be an 83.
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