document.write( "Question 274080: I am working with a data set that is normally distributed, with a mean of 200 and a standard deviation of 47. I need to determine the value of x from the following information:
\n" ); document.write( "a) 60% fo the values are greater than x
\n" ); document.write( "b) x is less than 17% of the values
\n" ); document.write( "c) 22% of the values are less than x
\n" ); document.write( "d) x is greater than 55% of the values.
\n" ); document.write( "

Algebra.Com's Answer #200083 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
I am working with a data set that is normally distributed, with a mean of 200 and a standard deviation of 47. I need to determine the value of x from the following information:
\n" ); document.write( "----
\n" ); document.write( "Please draw a picture of the normal curve so you can see what
\n" ); document.write( "these problems are asking you to find.
\n" ); document.write( "Put 200 at the middle mark and note that sigma = 47.
\n" ); document.write( "--------\r
\n" ); document.write( "\n" ); document.write( "a) 60% of the values are greater than x
\n" ); document.write( "So you want a right tail that has 60% of the area in it.
\n" ); document.write( "1st: Find the z-value that marks off that region:
\n" ); document.write( "invNorm(0.4) = -0.2533
\n" ); document.write( "2nd: Find the corresponding \"x\" value using
\n" ); document.write( "x = z*sigma + u
\n" ); document.write( "x = -0.2533*47 + 200
\n" ); document.write( "x = 188.09
\n" ); document.write( "============================================\r
\n" ); document.write( "\n" ); document.write( "b) x is less than 17% of the values
\n" ); document.write( "Right-tail has 17% of the area
\n" ); document.write( "z value = invNorm(0.83) = 0.9542
\n" ); document.write( "x value = 0.9542*47+200 = 244.85
\n" ); document.write( "=============================================\r
\n" ); document.write( "\n" ); document.write( "c) 22% of the values are less than x
\n" ); document.write( "Left-tail of 22%
\n" ); document.write( "z-value = invNorm(0.22) = -0.7722
\n" ); document.write( "x-value = -0.7722*47+200 = 163.71
\n" ); document.write( "=============================================
\n" ); document.write( "d) x is greater than 55% of the values
\n" ); document.write( "Left-tail of 55%
\n" ); document.write( "z-value = invNorm(0.55) = 0.1257
\n" ); document.write( "x-value = 0.1257*47+200 = 205.91
\n" ); document.write( "=============================================
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
\n" ); document.write( "
\n" ); document.write( "
\n" );