Table 1 Contingency table at jth failure time t_j

P ₁

n _{1 j}

λ_j−n_1j

λ _j

P ₀

n_j−n_1j

Y_j−λ_j−n_j+n_1j

Y_j−λ_j

Col totals

n _j

Y_j−n_j

Y _j