对于同一组资料，以下哪项没有考虑到每个观察值的变异（）。
A.方差
B.样本标准差
C.总体标准差
D.四分位数间距
E.变异系数
参考答案：D
I was very busy that day. Otherwise I _________in the discussion．
A．would take party
B．had taken part
C．took part
D．would have taken part
装运哪些货物需要施封？什么情况下可以不施封？
