A.20
B.22
C.24
D.28
E.30
[单选题]A.20B.22C.24D.28E.30
[单选题]A.16256B.-16256C.16384D.8128E.-8128
[单选题]方差σ2/x有:()。A.B.C.D.
[单选题]方差σ2/x有:()。A.B.C.D.
[单选题]A.B.C.D.