document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=195602>Question 195602</A>: <I><SPAN STYLE=\"word-break: break-all;\"> plS help me!.. URgent..I need your cooperatioN!\r<BR>\n" );
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document.write( "#1 problem:<BR>\n" );
document.write( "The Old Farmer's Almanac reports that the average person uses 123 gallons of water daily. If the standard deviation is 21 gallons, find the probability that the mean of a randomly selected sample of 15 people will be between 120 and 126 gallons. Assume the variable is normally distributed.\r<BR>\n" );
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document.write( "#2 problem:<BR>\n" );
document.write( "Procter & Gamble reported that an American family of four washes an average of 1 ton (2000 pounds) of clothes each year. If the standard deviation of the distribution is 187.5 pounds, find the probability that the mean of a randomly selected sample of 50 families of four will be between 1980 and 1990 pounds.\r<BR>\n" );
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document.write( "#3 problem:<BR>\n" );
document.write( "The average time it takes a group of adults to complete a certain achievement test is 46.2 minutes. The standard deviation is 8 minutes. Assume the variable is normally distributed.<BR>\n" );
document.write( "a.) Find the probability that a randomly selected adult will complete the test in less than 43 minutes.<BR>\n" );
document.write( "b.) Find the probability that, if 50 randomly selected adult take the test, the mean time it takes the group to complete the test will be less than 43 minutes.<BR>\n" );
document.write( "c.)Does it seem reasonable that an adult would finish the test in less than 43 minutes? Explain. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #146695 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=146695\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> #1 problem:<BR>\n" );
document.write( "The Old Farmer's Almanac reports that the average person uses 123 gallons of water daily. If the standard deviation is 21 gallons, find the probability that the mean of a randomly selected sample of 15 people will be between 120 and 126 gallons. Assume the variable is normally distributed. <BR>\n" );
document.write( "#2 problem:<BR>\n" );
document.write( "Procter & Gamble reported that an American family of four washes an average of 1 ton (2000 pounds) of clothes each year. If the standard deviation of the distribution is 187.5 pounds, find the probability that the mean of a randomly selected sample of 50 families of four will be between 1980 and 1990 pounds. <BR>\n" );
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document.write( "Find the z-values of 1980 and 1990<BR>\n" );
document.write( "z(1980) = (1980-2000)/[187.5/sqrt(50)]  = -0.7542<BR>\n" );
document.write( "z(1990) = (1990-2000)/[187.5/sqrt(50)]  = -0.37712<BR>\n" );
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document.write( "The P(1980 < xbar < 1990) = P(-0.7542 < z < -0.3771) = 0.1277<BR>\n" );
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document.write( "#3 problem:<BR>\n" );
document.write( "The average time it takes a group of adults to complete a certain achievement test is 46.2 minutes. The standard deviation is 8 minutes. Assume the variable is normally distributed.<BR>\n" );
document.write( "a.) Find the probability that a randomly selected adult will complete the test in less than 43 minutes.<BR>\n" );
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document.write( "z(43) = (43-46.2)/8 = -0.4<BR>\n" );
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document.write( "P(x < 43) = P(z < -0.4) = 0.3446<BR>\n" );
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document.write( "b.) Find the probability that, if 50 randomly selected adults take the test, the mean time it takes the group to complete the test will be less than 43 minutes.<BR>\n" );
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document.write( "z(43) = (43-46.2)/[8/sqrt(50)] = -2.8284<BR>\n" );
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document.write( "P(xbar < 43) = P(z < -2.8284) = 0.0023<BR>\n" );
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document.write( "c.)Does it seem reasonable that an adult would finish the test in less than 43 minutes? Explain.<BR>\n" );
document.write( "He has better than a 34% chance of doing that, as seen above.<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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