document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=929413>Question 929413</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The wait time for a company before a customer can talk to a customer service representative has a mean of 140 seconds with a standard deviation of 20 seconds. Suppose the distribution of wait times is approximately bell-shaped and symmetric.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Which one of the following statements is correct?<BR>\n" );
document.write( "	\r<BR>\n" );
document.write( "\n" );
document.write( "		A		The proportion of customers whose wait time is under 120 seconds is approximately 68%<BR>\n" );
document.write( "		B		The proportion of customers whose wait time is under 120 seconds is approximately 95%<BR>\n" );
document.write( "		C		The proportion of customers whose wait time is more than 160 seconds is approximately 84%<BR>\n" );
document.write( "		D		The proportion of customers whose wait time is more than 160 seconds is approximately 16%<BR>\n" );
document.write( "		E		The proportion of customers whose wait time is more than 140 seconds is greater than the proportion whose wait time is under 140 seconds </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #564262 by </B><A HREF=/tutors/aboutme.mpl?userid=ewatrrr><B>ewatrrr(24785)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ewatrrr><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=ewatrrr><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=564262\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> mean =140sec, SD = 20 seconds, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=z+=+blue%28x+-+140%29%2Fblue%2820%29 ALIGN=MIDDLE  ALT=\"z+=+blue%28x+-+140%29%2Fblue%2820%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >    <BR>\n" );
document.write( "...<BR>\n" );
document.write( "P(x < 120) = p( z < -20/20) = normalcdf(-100,-1) = .1587<BR>\n" );
document.write( "P(x > 120) = P(z > -1) = normalcdf(-1,100) = .8413<BR>\n" );
document.write( "P(x > 160) = P(z > 20/20)= normalcdf(1,100) = .1587 0r 15.87% ***<BR>\n" );
document.write( ".5000 = .5000<BR>\n" );
document.write( "D.<BR>\n" );
document.write( ".......<BR>\n" );
document.write( "For the normal distribution: Below:  z = 0, z = ± 1, z= ±2 , z= ±3 are plotted.  <BR>\n" );
document.write( "Area under the standard normal curve to the left of the particular z is P(z)<BR>\n" );
document.write( "Note: z = 0 (x value: the mean) 50% of the area under the curve is to the left and 50%  to the right<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=drawing%28400%2C200%2C-5%2C5%2C-.5%2C1.5%2C+graph%28400%2C200%2C-5%2C5%2C-.5%2C1.5%2C+exp%28-x%5E2%2F2%29%29%2C+green%28line%281%2C0%2C1%2Cexp%28-1%5E2%2F2%29%29%2Cline%28-1%2C0%2C-1%2Cexp%28-1%5E2%2F2%29%29%29%2Cgreen%28line%282%2C0%2C2%2Cexp%28-2%5E2%2F2%29%29%2Cline%28-2%2C0%2C-2%2Cexp%28-2%5E2%2F2%29%29%29%2Cgreen%28line%283%2C0%2C3%2Cexp%28-3%5E2%2F2%29%29%2Cline%28-3%2C0%2C-3%2Cexp%28-3%5E2%2F2%29%29%29%2Cgreen%28line%28+0%2C0%2C+0%2Cexp%280%5E2%2F2%29%29%29%2Clocate%284.8%2C-.01%2Cz%29%2Clocate%284.8%2C.2%2Cz%29%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );