NO.PZ2023091601000056
问题如下：
An analyst wants to test
whether the standard deviation of return from pharmaceutical stocks is lower
than 0.2. For this purpose, he obtains the following data from a sample of 30
pharmaceutical stocks. Mean return from pharmaceutical stocks = 8%. Standard
deviation of return from pharmaceutical stocks = 12%. Mean return from the
market = 12%. Standard deviation of return from the market = 16%. What is the
appropriate test statistic for this test?
选项：
A.
t-statistic
B.
z-statistic
C.
F-statistic
D.
χ2 statistic
解释：
Tests of the variance
(or standard deviation) of a population requires the chi-squared test.
老师好，咱们只学过某一个分布的均值是否等于确定的数，某一个分布的方差是否等于确定的数，两个分布的方差是否相等，两个分布的均值是否相等。那这道题是可以用卡放分布的？也就是某一个分布的方差大于或小于某个值的计算方法与某一个分布的方差是否等于确定的数的计算方法是一样的？那我图中的计算过程对吗？
