function p=age(x,y,z)

% x= age in years;
% y= severity of emphysema (0= no emphysema, 1= mild emphysema, etc.)
% z= cholesterol level (0= low, ..., 4= highly elevated)

mu= 45 + 6*y + 6*(z-2);
if x <= mu
   p= 0.025*(x-20)/(mu-20);
else
   p= 0.025*(100-x)/(100-mu);
end
