 Mathematically, this is equivalent to the following. Let \(U_L\) be the error variable for \(L. U_L\) takes values of the form \((u_1, u_2)\) with each \(u_i\) being 0 or 1. \((1, 1)\) corresponds to doomed, \((0, 0)\) to immune, \((1, 0)\) to sensitive, and \((0, 1)\) to reverse. That is, the first element tells us what value L will take if an individual is exposed to asbestos, and the second element what value L will take if an individual is not exposed. The equation for L will be \(L = (A \times u_1) + ((1 - A) \times u_2)\).