document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1051786>Question 1051786</A>: <I><SPAN STYLE=\"word-break: break-all;\"> From past experience, a company found that in cartons of DVDs, 90% contain no defective DVDs, 5% contain one defective DVD, 3% contain two defective DVDs, and 2% contain three defective DVDs. Find the mean, variance, and standard deviation for the number of defective DVDs. Please explain all steps.<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 #667252 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=667252\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> From past experience, a company found that in cartons of DVDs, 90% contain no defective DVDs, 5% contain one defective DVD, 3% contain two defective DVDs, and 2% contain three defective DVDs. Find the mean, variance, and standard deviation for the number of defective DVDs. Please explain all steps.<BR>\n" );
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document.write( "Percent of defective = 100%-90% = 10%<BR>\n" );
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document.write( "mean = n*p = 0.1*n<BR>\n" );
document.write( "variance = n*p*q = 0.1n*0.9 = 0.09n<BR>\n" );
document.write( "std = sqrt(npq) = sqrt(0.09n) = 0.3*sqrt(n)<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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