document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=322734>Question 322734</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Light Bulb Life Span • The life span of a certain type of light bulb is normally distributed with a mean of 5000 hours and a standard deviation of 150 hours.  Estimate the probability that this type of light bulb has a life span is between 4850 and 5300 hours.\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 #231022 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=231022\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Light Bulb Life Span • The life span of a certain type of light bulb is normally distributed with a mean of 5000 hours and a standard deviation of 150 hours. Estimate the probability that this type of light bulb has a life span is between 4850 and 5300 hours. <BR>\n" );
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document.write( "z(4850) = (4850-5000)/150 = -1<BR>\n" );
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document.write( "z(5300) = (5300-5000)/150 = 2<BR>\n" );
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document.write( "P(4850 < x < 5300) = P( -1 < z < 2) = 0.8186<BR>\n" );
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document.write( "Comment: This is a standard procedure.  Are you beginning<BR>\n" );
document.write( "to understand it?<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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