document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=997213>Question 997213</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a researcher was interested to study variations in number of deaths from two types of events. He considered number of deaths from HIV a random variable(x) and number of deaths from a car accident a random variable (Y). He is interested in the total death due to the  Two events. He named This random variable  Z(Z=X+Y). What would be the mean for Z?<BR>\n" );
document.write( "  var (x)=2.3   and var (y)=1.8 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #615441 by </B><A HREF=/tutors/aboutme.mpl?userid=mathmate><B>mathmate(429)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mathmate><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=mathmate><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=615441\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\">  <BR>\n" );
document.write( "Given:<BR>\n" );
document.write( "Two (assumed) independent variables X, Y, each with variance var(x)=2.3 and 1.8, and mean <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=mu+x ALIGN=MIDDLE  ALT=\"mu+x\"   DISABLED_style= \"max-width:90%; height:auto;\" > and <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=mu+y ALIGN=MIDDLE  ALT=\"mu+y\"   DISABLED_style= \"max-width:90%; height:auto;\" >respectively<BR>\n" );
document.write( " <BR>\n" );
document.write( "To Find:<BR>\n" );
document.write( "Mean of total, Z=X+Y.<BR>\n" );
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document.write( "Solution:<BR>\n" );
document.write( "The mean of the sum of two independent variables X, Y <BR>\n" );
document.write( "= <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=mu+x+%2B+mu+y ALIGN=MIDDLE  ALT=\"mu+x+%2B+mu+y\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The variance of the sum of two independent variables X, Y <BR>\n" );
document.write( "= <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=var%28X%29%2Bvar%28Y%29=2.3%2B1.8=4.1 ALIGN=MIDDLE  ALT=\"var%28X%29%2Bvar%28Y%29=2.3%2B1.8=4.1\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );