The linear model takes an input vector of dimension d and computes g = Sum(i=1,d,w_i*x_i)-t The w_i are called weights and t is the threshold. A good error function is: E(w_i,t)=Sum(n=1,N,(g_wt(x_n)-y_n)^2) To solve for the optimal w_i and t, take dE/dw_i = 0 and dE/dt = 0 and solve for w_i and t