document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=296061>Question 296061</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I need help in my statistics class with exercises 8.46 and 8.62 in my textbook.<BR>\n" );
document.write( "The problems are listed below.\r<BR>\n" );
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document.write( "8.46<BR>\n" );
document.write( "A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on<BR>\n" );
document.write( "a very accurate scale. The results in grams were<BR>\n" );
document.write( "3.087 3.131 3.241 3.241 3.270 3.353 3.400 3.411 3.437 3.477<BR>\n" );
document.write( "(a) Construct a 90 percent confidence interval for the true mean weight. (b) What sample size<BR>\n" );
document.write( "would be necessary to estimate the true weight with an error of ± 0.03 grams with 90 percent confidence?<BR>\n" );
document.write( "(c) Discuss the factors which might cause variation in the weight of Tootsie Rolls during<BR>\n" );
document.write( "manufacture. <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 #213409 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=213409\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on a very accurate scale. The results in grams were<BR>\n" );
document.write( "3.087 3.131 3.241 3.241 3.270 3.353 3.400 3.411 3.437 3.477<BR>\n" );
document.write( "(a) Construct a 90 percent confidence interval for the true mean weight.<BR>\n" );
document.write( "A T-Interval is (3.2283,3.3813)<BR>\n" );
document.write( "The sample mean is 3.304800 and E= 0.076500<BR>\n" );
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document.write( "(b) What sample size would be necessary to estimate the true weight with an error of ± 0.03 grams with 90 percent confidence?<BR>\n" );
document.write( "n = [t*sigma/0.03]^2<BR>\n" );
document.write( "n = [1.645*0.131989/0.03]^2<BR>\n" );
document.write( "n = 7.237397^2<BR>\n" );
document.write( "n = 52.3799<BR>\n" );
document.write( "n= 53 rounding up<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. <BR>\n" );
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document.write( "I'll leave (c) to you.<BR>\n" );
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document.write( "(c) Discuss the factors which might cause variation in the weight of Tootsie Rolls during manufacture.\r<BR>\n" );
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document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );