document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1169990>Question 1169990</A>: <I><SPAN STYLE=\"word-break: break-all;\"> suppose that the lifetimes of light bulbs are approximately normally​ distributed, with a mean of 57 hours and a standard deviation 3.3 of hours. with this​ information, answer the following questions. ​<BR>\n" );
document.write( "(a) what proportion of light bulbs will last more than 60 ​hours? ​<BR>\n" );
document.write( "(b) what proportion of light bulbs will last 51 hours or​ less? <BR>\n" );
document.write( "​(c) what proportion of light bulbs will last between 57 and 61 ​hours? ​<BR>\n" );
document.write( "(d) what is the probability that a randomly selected light bulb lasts less than 45 ​hours? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #795252 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=795252\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> z=(x-mean)/sd<BR>\n" );
document.write( "the first will be z > 3/3.3 or z > 0.909 . That probability is 0.1817<BR>\n" );
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document.write( "the second will be z < -6/3.3 and that probability is 0.0345<BR>\n" );
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document.write( "the third is 0.3873. Calculator 2ndVARS 2 normalcdf(57,61,57,3.3)ENTER<BR>\n" );
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document.write( "the last is z < -12/3.3 and probability is 0.0001 </SPAN>\n" );
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