document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=428557>Question 428557</A>: <I><SPAN STYLE=\"word-break: break-all;\"> It has been observed that electrical connectors manufactured by Jolt Electrical Supply Company last an average of 18.2 months and follow a normal distribution with a standard deviation of 1.7 months.  Jolt agrees to replace any connector that fails within 19 months.  Out of 500 connectors sold, how many does Jolt expect to replace, on average? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #297846 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=297846\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> It has been observed that electrical connectors manufactured by Jolt Electrical Supply Company last an average of 18.2 months and follow a normal distribution with a standard deviation of 1.7 months. Jolt agrees to replace any connector that fails within 19 months. Out of 500 connectors sold, how many does Jolt expect to replace, on average?<BR>\n" );
document.write( "----<BR>\n" );
document.write( "z(19) = (19-18.2)/1.7 = 0.4706<BR>\n" );
document.write( "P(x< 19) = P(z< 0.4706) = 0.6810<BR>\n" );
document.write( "-------------<BR>\n" );
document.write( "So 68.1% will last up to 19 mths.<BR>\n" );
document.write( "So 0.3190 will fail in that period.<BR>\n" );
document.write( "Jolt can expect to replace 0.319*500 = 160 units.<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( "==============<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );