Grayson · 2022年01月15日
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。
B选项为什么错误？每一个的概率不都是0.5，所以是uniform？
NO.PZ2017092702000080问题如下For a binomiranm variable with five trials, ana probability of success on eatriof 0.50, the stribution will be:A.skeweB.uniform.C.symmetric. C is correct. The binomistribution is symmetric when the probability of success on a triis 0.50, but it is asymmetric or skeweotherwise. Here it is given thp = 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。 这个问题对应讲义的哪部分内容呢？
NO.PZ2017092702000080问题如下 For a binomiranm variable with five trials, ana probability of success on eatriof 0.50, the stribution will be:A.skeweB.uniform.C.symmetric. C is correct. The binomistribution is symmetric when the probability of success on a triis 0.50, but it is asymmetric or skeweotherwise. Here it is given thp = 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？能画图下吗
所以这道题就是记住 P=0.5 binominstribution is symmetric嘛？结论怎么来的呢？
我看到助教之前的解答里，“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。” 请问这是为什么呀
