66 The score equations for the full sample are: m exp(a+i) ∑ exp(a+Bxi) =0 (1) i=1 -+=0 (2) i=1 x一业 =0 02 (3) i=1 n +0 2o4 (4) i=1 Note that Equations (3)and (4)can be solved explicitly to get solutions for a and 62,i.e., 在= 一 Ti ∑a:-创2 i=1 i=66 The score equations for the full sample are:  n i=1 ri − exp(α + βxi) 1 + exp(α + βxi) = 0 (1)  n i=1 xi(ri − exp(α + βxi) 1 + exp(α + βxi)) = 0 (2)  n i=1 xi − µ σ2 = 0 (3)  n i=1 − 1 2σ2 + (xi − µ)2 2σ4 = 0 (4) Note that Equations (3) and (4) can be solved explicitly to get solutions for ˆµ and ˆσ2, i.e., µ ˆ = 1 n  n i=1 xi and ˆσ2 = 1 n  n i=1 (xi − µˆ)2