document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=322162>Question 322162</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 4. Answer the questions about the specified normal distribution. \r<BR>\n" );
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document.write( "a.The lifetime of ZZZ batteries are normally distributed with a mean of 270 hours and a standard deviation &#61555; of 10 hours. Find the number of hours that represent the 40th percentile. \r<BR>\n" );
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document.write( "b.Scores on an English placement test are normally distributed with a mean of 55 and standard deviation &#61555; of 6.5. Find the score that marks the top 5%. <BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #230628 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=230628\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> a.The lifetime of ZZZ batteries are normally distributed with a mean of 270 hours and a standard deviation &#61555; of 10 hours. Find the number of hours that represent the 40th percentile.<BR>\n" );
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document.write( "Find the z-value that has a left tail of 40%<BR>\n" );
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document.write( "z = invNorm(0.40) = -0.2533<BR>\n" );
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document.write( "Find the corresponding x-value using x = zs+u:<BR>\n" );
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document.write( "x = -0.2533*10 + 270<BR>\n" );
document.write( "x = 267.46<BR>\n" );
document.write( "Round up to x = 268<BR>\n" );
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document.write( "b.Scores on an English placement test are normally distributed with a mean of 55 and standard deviation &#61555; of 6.5. Find the score that marks the top 5%.<BR>\n" );
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document.write( "Find the z-value with a left tail of 95%.<BR>\n" );
document.write( "invNorm(0.95) = 1.645<BR>\n" );
document.write( "Find the corresponding x value:<BR>\n" );
document.write( "x = 1.645*10+270 = 286.45<BR>\n" );
document.write( "Round up to x = 287<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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