load soi88.dat
x    = soi88;
r    = [x(2:4,2)./x(2:4,1),x(2:4,4)./x(2:4,3);
        (x(1,2)-sum(x(2:5,2)))/(x(1,1)-sum(x(2:5,1))), ...
        (x(1,4)-sum(x(2:5,4)))/(x(1,3)-sum(x(2:5,3)))];

plot(r,'-o')

