document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=57673>Question 57673</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I been working out this problem but I'm not sure if my answer is right. \r<BR>\n" );
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document.write( "Among U.S households, 24% have telephone answering machines, if a telemarketin campaign involves 2500 households, find the probability that more than 650 have answering machines.\r<BR>\n" );
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document.write( "My solution:\r<BR>\n" );
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document.write( "mean   =2500 x .24 =600<BR>\n" );
document.write( "std. d =sq.root of 2500 x.24 x.76 =sq.root of 450 = 21\r<BR>\n" );
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document.write( "650-600/21= 2.38 = .9813 ?\r<BR>\n" );
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document.write( "Thanks a lot! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #39618 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=39618\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> I been working out this problem but I'm not sure if my answer is right. <BR>\n" );
document.write( "Among U.S households, 24% have telephone answering machines, if a telemarketin campaign involves 2500 households, find the probability that more than 650 have answering machines. <BR>\n" );
document.write( "My solution: <BR>\n" );
document.write( "mean =2500 x .24 =600<BR>\n" );
document.write( "std. d =sq.root of 2500 x.24 x.76 =sq.root of 450 = 21 <BR>\n" );
document.write( "650-600/21= 2.38 = .9813 ? <BR>\n" );
document.write( "Thanks a lot!<BR>\n" );
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document.write( "Everything looks good until you get to <BR>\n" );
document.write( "\"650-600/21= 2.38 = .9813 ?\"<BR>\n" );
document.write( "You calculated the z-score corresponding to 650<BR>\n" );
document.write( "and got 2.38.<BR>\n" );
document.write( "The Probability you are looking for is <BR>\n" );
document.write( "Prob (X>650)=Prob(z>2.38)<BR>\n" );
document.write( "That probability is 0.00865...<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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