NO.PZ2015120604000132
问题如下：
Which of the following is the most accurate statements about hypothesis testing?
选项：
A.
The calculated z-statistic for a test of a single variance is known as: 
(σ2 is the variance).
B.
If the computed z-statistic = -3 and the critical z-value = -2, the null hypothesis should be accepted.
C.
the probability of the Type I error equals the significance level.
解释：
C is correct.
The z-statistic is used for the test of the mean not variance .
If the computed z-statistic = -3 and the critical z-value = -2, the null hypothesis should be rejected.
type 1 error等于显著性水平，请问是怎么推导出来的？ 还有A选项，明白是检验均值的，想确认下关于Z statistic的计算公式是对的吗？
