已知随机变量X服从B ( n , p ),E(X) = 4,D(X) = 3.6,则( ).
A: n = 20,p = 0.2
B: n = 40,p = 0.9
C: n = 10,p = 0.4
D: n = 40,p = 0.1
A: n = 20,p = 0.2
B: n = 40,p = 0.9
C: n = 10,p = 0.4
D: n = 40,p = 0.1
举一反三
- 已知X服从二项分布B(n,p),E(X)=4,D(X)=2.4,则 A: n=8,p=0.5 B: n=10.p=0.4 C: n=20,p=0.2 D: n=5,p=0.2
- 已知随机变量X服从B ( n , p ),E(X) = 2.4,D(X) = 1.68,则( ). A: n = 4,p = 0.6 B: n = 6,p = 0.4 C: n = 8,p = 0.3 D: n = 24,p = 0.1
- 已知随机变量X服从B ( n , p ),E(X) = 2.4,D(X) = 1.44,则( ). A: n = 4,p = 0.6 B: n = 6,p = 0.4 C: n = 8,p = 0.3 D: n = 24,p = 0.1
- 设随机变量X~B(n,p),且E(X)=1.6,D(X)=1.28,则_________。? n=7,p=0.45|n=5,p=0.32|n=4,p=0.4|n=8,p=0.2
- 若X服从二項分布B(n,p),且E(X)=6,D(X)=4.2,则以下正确的是()。 A: n=25,p=0.25 B: n=30,p=0.2 C: n=40,p=0.1 D: n=20,p=0.3