np . random . seed (5) N = 100 pi = 0.3 q0 = 0. 05 q1 = 0. 18 n1 = int (N * pi) n0 = N - n1 y_obs = np . zeros (N) y_obs [:n0] = np. random . geometric (q0, size=n0) y_ obs [n0:] = np. random . geometric (q1, size=n1)