document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=469024>Question 469024</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I need a tutor to review these and tell me if I am performing the operations correctly. I am not sure if I am going about it right...\r<BR>\n" );
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document.write( "Suppose the scores of certain standardized test are normally distributed with mean 500 and standard<BR>\n" );
document.write( "deviation 60.\r<BR>\n" );
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document.write( "8. (1 point) What percent of the test takers have a score of 440 or less? Round answer to four places after<BR>\n" );
document.write( "the decimal point.\r<BR>\n" );
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document.write( "500-440= 60/60 = 1<BR>\n" );
document.write( "1= .8413\r<BR>\n" );
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document.write( "9. (1 point) What percent of the test takers have a score of 590 or more? Round answer to four places<BR>\n" );
document.write( "after the decimal point.\r<BR>\n" );
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document.write( "590-500= 90/60= 1.5<BR>\n" );
document.write( "1.5= .9332\r<BR>\n" );
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document.write( "10. (1 point) What percent of the test takers have a score between 440 and 590? Round answer to four<BR>\n" );
document.write( "places after the decimal point.\r<BR>\n" );
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document.write( ".9332-.8413= 1.5 - 1 = .6915\r<BR>\n" );
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document.write( "11. (1 point) Suppose a college will only admit students who score in the top 20% among all test takers,<BR>\n" );
document.write( "what will be the minimum required score be? Round answer to the nearest whole number.\r<BR>\n" );
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document.write( ".20= .8416 = x-500= 80.496= 580 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #321822 by </B><A HREF=/tutors/aboutme.mpl?userid=ccs2011><B>ccs2011(207)</B></A><img src=\"/images/stars/stars-09.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ccs2011><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=ccs2011><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=321822\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <BR>\n" );
document.write( "Z = (x-u)/s, where u=mean, s=std deviation<BR>\n" );
document.write( "The probabilities given always are for less than or equal to that number.<BR>\n" );
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document.write( "8. you used 1 instead of -1:<BR>\n" );
document.write( "Always subtract the mean, if its smaller you should get a negative Z<BR>\n" );
document.write( "For Z = -1, P = .1587<BR>\n" );
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document.write( "9. Look at question, they want scores greater than 590.<BR>\n" );
document.write( "For Z= 1.5, P = .9332<BR>\n" );
document.write( "So 93% are less, the compliment is 1-P<BR>\n" );
document.write( "1-P = .0668<BR>\n" );
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document.write( "10. Don't subtract Z values, only P values<BR>\n" );
document.write( "Take P from 590 and subtract P from 440<BR>\n" );
document.write( ".9332 - .1587 = .7745<BR>\n" );
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document.write( "11. Top 20% also means that at that score 80% will be less than that score.<BR>\n" );
document.write( "Find Z such that P=0.8<BR>\n" );
document.write( "Corresponding Z is .8416<BR>\n" );
document.write( "Find x using this value.<BR>\n" );
document.write( "(x-500)/60 = .8416<BR>\n" );
document.write( "x-500 = 50<BR>\n" );
document.write( "x = 550<BR>\n" );
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