document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1049353>Question 1049353</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I really need assistance with this question:\r<BR>\n" );
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document.write( "Men’s weights are normally distributed with mean 170 pounds and standard deviation 20 pounds.\r<BR>\n" );
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document.write( "(a)  Find the probability that a randomly selected man has a weight between 140 and 190. (Show work and round the answer to 4 decimal places)\r<BR>\n" );
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document.write( "(b) What is the 80th percentile for men’s weight? (Show work and round the answer to 2 decimal places)\r<BR>\n" );
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document.write( "(c) If 64 men are randomly selected, find the probability that sample mean weight is greater than 175. (Show work and round the answer to 4 decimal places)\r<BR>\n" );
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document.write( "I really appreciate any help, thank you!<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 #664893 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=664893\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Men’s weights are normally distributed with mean 170 pounds and standard deviation 20 pounds. <BR>\n" );
document.write( "(a) Find the probability that a randomly selected man has a weight between 140 and 190. (Show work and round the answer to 4 decimal places)<BR>\n" );
document.write( "z(140) = (140-170)/20 = -3/2<BR>\n" );
document.write( "z(190) = (190-170)/20 = 1<BR>\n" );
document.write( "P(140< x < 190) = P(-3/2< z < 1) = normalcdf(-3/2,1) = 0.7745<BR>\n" );
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document.write( "(b) What is the 80th percentile for men’s weight? (Show work and round the answer to 2 decimal places)<BR>\n" );
document.write( " Find the z-value with a left-tail of 0.80:: invNorm(0.8) = 0.8416<BR>\n" );
document.write( "That means the 80th percentile value is 0.8416 standard deviations<BR>\n" );
document.write( "above the mean.<BR>\n" );
document.write( "Find that value using x = z*s + u<BR>\n" );
document.write( "Ans: x = 0.8416*20 + 170 = 186.83 lbs<BR>\n" );
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document.write( "(c) If 64 men are randomly selected, find the probability that sample mean weight is greater than 175. (Show work and round the answer to 4 decimal places)<BR>\n" );
document.write( "mean of sample mean = 170<BR>\n" );
document.write( "std of sample means = 20/sqrt(64) = 20/8 = 5/2<BR>\n" );
document.write( "z(175) = (175-170)/(5/2) = 5/(5/2) = 2<BR>\n" );
document.write( "P(x > 175) = P(z > 2) = normalcdf(2,100) = 0.0228<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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