NO.PZ2017092702000080
问题如下:
For a binomial random variable with five trials, and a probability of success on each trial of 0.50, the distribution will be:
选项:
A.
skewed.
B.
uniform.
C.
symmetric.
解释:
C is correct.
The binomial distribution is symmetric when the probability of success on a trial is 0.50, but it is asymmetric or skewed otherwise. Here it is given that p = 0.50
当试验成功的概率为 0.50 时,二项分布是对称的。另当p=0.1时二项分布是右偏的,当p=0.9时二项分布是左偏的。
为何P小于0.5是右,大于是左?能画图解释下吗