13995173783 · 2023年06月08日
NO.PZ2020010302000009
问题如下：
Consider the following data on a discrete random variable X:
a. Calculate the mean and variance of X.
b. Standardize X and check that the mean and variance of X are 0 and 1 respectively.
c. Calculate the skew and kurtosis of X.
选项：
解释：
a. The mean is -0.803 and the variance is 6.762.
b.
DD仔_品职助教 · 2023年06月08日
嗨，从没放弃的小努力你好：
同学你好，
Xstandardised叫做标准化，含义是将一个均值和方差任意的正态分布，对应成均值=0，方差=1的标准正态分布。因为分布的目的是想到得出概率，而正态分布可以根据均值和方差的不同有千千万万种，为了方便起见，就对于这些任意的正态分布进行标准化，都归正成为对峙=0，方差=1的标准正态分布，这样的话只需要准备一张标准正态的分布概率表，就可以查询任意分布的概率了。
variance就是方差，所以标准化的方差=1.
----------------------------------------------加油吧，让我们一起遇见更好的自己！
NO.PZ2020010302000009 问题如下 Consir the following ta on a screte ranm variable X:Calculate the meanvarianof X. Stanrze X ancheththe meanvarianof X are 0 an1 respectively.Calculate the skew ankurtosis of X. The meis -0.803 anthe varianis 6.762.b.c.Hence, the skew of X is -0.581 anthe kurtosis of X is 2.773. 我看回答里需要准备一张标准正态的分布概率表，意思是考试我们把还需要带一张准备一张标准正态的分布概率表吗？
NO.PZ2020010302000009 问题如下 Consir the following ta on a screte ranm variable X:Calculate the meanvarianof X. Stanrze X ancheththe meanvarianof X are 0 an1 respectively.Calculate the skew ankurtosis of X. The meis -0.803 anthe varianis 6.762.b.c.Hence, the skew of X is -0.581 anthe kurtosis of X is 2.773. 如果在计算过程中，发现数字输或符号输入有误，怎样删除现有的错误数字或符号而不影响计算过程？
NO.PZ2020010302000009 问题如下 Consir the following ta on a screte ranm variable X:Calculate the meanvarianof X. Stanrze X ancheththe meanvarianof X are 0 an1 respectively.Calculate the skew ankurtosis of X. The meis -0.803 anthe varianis 6.762.b.c.Hence, the skew of X is -0.581 anthe kurtosis of X is 2.773. 具体怎么标准化的，能写出来标准化的具体过程么。谢谢
NO.PZ2020010302000009问题如下Consir the following ta on a screte ranm variable X:Calculate the meanvarianof X. Stanrze X ancheththe meanvarianof X are 0 an1 respectively.Calculate the skew ankurtosis of X.The meis -0.803 anthe varianis 6.762.b.c.Hence, the skew of X is -0.581 anthe kurtosis of X is 2.773.手算还是计算器算，。
