1 EX=0.1
EY=0.08
2 EX^2=0.0176 DX=0.0076
EY^2=0.01348 DY=0.00708
3COVXY=EXY-EXEY=
4Z=.3X+.7Y
EZ=0.086
DZ=DX+DY-2COVX,Y