document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1191723>Question 1191723</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A light bulb manufacturer finds that 5% of his bulbs last more than 500 hours. An improvement in the process meant that the mean lifetime was increased by 50 hours . In a new test, 20% of bulbs now lasted longer than 500 hours.<BR>\n" );
document.write( "          Find the mean and standard deviation of the    original process\r<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 #823552 by </B><A HREF=/tutors/aboutme.mpl?userid=ikleyn><B>ikleyn(52781)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ikleyn><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=ikleyn><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=823552\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> .\r<BR>\n" );
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document.write( "Looking at this problem, I'd say that its formulation is incorrect (or incomplete).\r<BR>\n" );
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document.write( "Would it be correct and complete, it must say that the standard deviation after improvement remained the same as before it.\r<BR>\n" );
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document.write( "Since the problem is silent about it (leaving it for the reader to guess), this problem is more like a puzzle than a Math problem.\r<BR>\n" );
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