小n(x) N(0,1)(t-(x) tho(x) ts(x) 启 t(x) 5 -4-3-2 -1 0 12 3 4 Previous Next First Last Back Forward 8−4 −3 −2 −1 0 1 2 3 4 0.1 0.2 0.3 0.4 x tn(x) N(0, 1)(t∞(x)) t10(x) t5(x) t1(x) Previous Next First Last Back Forward 8