69.已知总体标准差,但样本含量不大,总体均-|||-数95%的可信区间用-|||-A. [ X-t0.025(v) (S)_(X) , +0.025(V)(S)_(X)] -|||-B. (X-1.96(S)_(X) , +1.96(S)_(X))-|||-C. (X-1.960X , +1.960X)-|||-D. (X-1.645(S)_(X) , +1.645(S)_(X))-|||-E. (X-2.58(S)_(X) , +2.58(S)_(X)