document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1187196>Question 1187196</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A report in a research journal states that the average weight loss of people on a certain drug is 35 lbs with a margin of error of ±3 lbs with confidence level CL = 95%.\r<BR>\n" );
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document.write( "(a) According to this information, the mean weight loss of people on this drug, 𝜇, could be as low as ___ lbs.\r<BR>\n" );
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document.write( "(b) If the study is repeated, how large should the sample size be so that the margin of error would be less than 1.5 lbs? (Assume 𝑆= 8 lbs.)<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 #819198 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=819198\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 32 pounds, the mean- the margin of error\r<BR>\n" );
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document.write( "margin of error is t*s/sqrt(n)=3 pounds.<BR>\n" );
document.write( "check to see if what the original sample size was with s=8<BR>\n" );
document.write( "t (df unknown, 0.975) is about 2 for unknown sample size*8/sqrt(n) and has to equal 3<BR>\n" );
document.write( "16/sqrt(n)=3; sqrt n=(16/3) n=256/9 or about 28.\r<BR>\n" );
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document.write( "error=t*s/sqrt(n); <BR>\n" );
document.write( "1.5 pounds=2*8/sqrt(n), guessing the value of t<BR>\n" );
document.write( "square both sides<BR>\n" );
document.write( "2.25=256/(n)<BR>\n" );
document.write( "n=256/2.25, or 114 rounded up.<BR>\n" );
document.write( "that is the answer given the t with df=113 is very close to 2.\r<BR>\n" );
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