A.Var(a)=0(a是常量)B.Var(aX)=a2Var(X)(a是常量)C.Var(XY)=Var(X)Var(Y)D.Var(X+Y)=Var(X)+Var(Y)(X和Y彼此獨(dú)立)
A.下四分位數(shù)為8.2B.上四分位數(shù)為9.6C.中位數(shù)為8.8D.變異系數(shù)為10.21%
A.調(diào)和平均數(shù)B.算術(shù)平均數(shù)C.幾何平均數(shù)D.上述都可以