document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1182351>Question 1182351</A>: <I><SPAN STYLE=\"word-break: break-all;\"> large construction firm estimates that the time required to complete a college complex is normally distribution with mean of 18 months and standard deviation of 2 months. What is the probability that it will take (i) at least one year and five month to complete it ? (ii) at most one year and eight months to complete it? (ii) between one year four months and one year ten months? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #812353 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=812353\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> z=(x-mean)/sd<BR>\n" );
document.write( "one year 5 months=17 months<BR>\n" );
document.write( "z=(17-18)/2 =-0.5<BR>\n" );
document.write( "for z > =-0.5 the probability is 0.6915<BR>\n" );
document.write( "-<BR>\n" );
document.write( "for at most 1y8m is 20 months<BR>\n" );
document.write( "z=(20-18)/2=1<BR>\n" );
document.write( "probability z < 1 is 0.8413<BR>\n" );
document.write( "-<BR>\n" );
document.write( "c is using 16 months and 22 months<BR>\n" );
document.write( "can use the calculator here as well.<BR>\n" );
document.write( "2ndVARS2normalcdf(16,22,18,2)ENTER, and that is low, high, the known mean, and the normal sd)<BR>\n" );
document.write( "=0.8186 probability<BR>\n" );
document.write( "That is also between -1 and +2 sd<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );