单项选择题
The following table contains the probability distribution for X = the number of retransmissions necessary to successfully transmit a 1024K data package through a double satellite media.
X
0
1
2
3
P(X)
0.35
0.35
0.25
0.05
the standard deviation of the number of retransmissions is ________
A．0.894X
0
1
2
3
P(X)
0.35
0.35
0.25
0.05
B．1
C．0.799
D．3
点击查看答案&解析
