Consider the following dynamic factor model: x_{it} = \lambda_{i0}f_t + \lambda_{i1}f_{t-1} + \lambda_{i2} f_{t-2} + e_{it}, t=1,2,...,T; I = 1,2,...,N; f_t = \phi_1 f_{t-1} + \eta_t; e_t = D_1 e_{t-1} + D_2 e_{t-2} + \psi_t where N = 4 and T = 200; e_t = (e_{1t}, e_{2t}, ......, e_{Nt})', the factor is scalar, and \eta_t and \psi_t are iid Normal and independent of each other. Let X_t = (x_{1t}, x_{2t}, ......, x_{Nt})'. Explain carefully which method you would use to estimate the model's parameters, writing down the exact equation(s) that you need to estimate with the chosen method