standard normal Z distribution

例句：

1. 1. Thestandard normal Z distribution is used to describe the probability distribution of a variable that follows a normal distribution.
   标准正态Z分布用于描述遵循正态分布的变量的概率分布。
2. 2. In statistics, the standard normal Z distribution is used to calculate the mean and standard deviation of a population.
   在统计学中，标准正态Z分布用于计算总体的均值和标准差。
3. 3. The standard normal Z distribution is often used in hypothesis testing to determine whether a sample is drawn froma population with a known mean and standard deviation.
   标准正态Z分布常用于假设检验中，以确定样本是否来自具有已知均值和标准差的群体。