function va=whatif(th)
for i=1:100
x=exprnd(1,1,5);
t1=min([x(1)+x(2) x(1)+x(3)+x(5)  x(4)+x(5)] );
t1=t1*exp((1-1/th)*sum(x))/th^5;
t=[t t1];
end
va=var(t);
