问题如下图：
选项：
A. 
B. 
C. 
D. 
解释：
完全不清楚，正常t检验不是自由度n-1么？怎么是n-2
NO.PZ2019040801000038 问题如下 termine if this proposition is correct: In a simple lineregression, the appropriate number of grees of freem for the critict-value useto calculate a confinintervequals to the number of observations minus two. A.correct. B.incorrect, because the number of grees of freem for the critict-value useto calculate a confinintervis the number of observations. C.incorrect, because the number of grees of freem for the critict-value useto calculate a confinintervis the number of observations minus one. incorrect, because the number of grees of freem for the critict-value useto calculate a confinintervis uncertain. A is correct.考点Hypothesis Test anLineRegression解析在一元线性回归中，用于用t检验值构造置信区间的自由度数量，等于样本数减去2。因此命题正确。 老师你好，这里怎么看出它是一元线性回归
NO.PZ2019040801000038 老师你好，想问下在lineregression里面用到hypothesis test的有检验b0和b1是否为0，这里的是等于n-1吗。然后用于检测CI的话，用的也是t test， 但是里面的=n-k-1对吧。为什么呢，跟用什么test没有关系跟检测什么有关吗。还有就是用t-test检测CI的话是指什么，就是检测b1是不是等于一个hypothesis value吗？谢谢
想请问在什么情况下可以选自由度是k呢？在求参数的自由度的时候？
incorrect, because the number of grees of freem for the critict-value useto calculate a confinintervis the number of observations. incorrect, because the number of grees of freem for the critict-value useto calculate a confinintervis the number of observations minus one. incorrect, because the number of grees of freem for the critict-value useto calculate a confinintervis uncertain. A is correct. 考点Hypothesis Test anLineRegression 解析在一元线性回归中，用于用t检验值构造置信区间的自由度数量，等于样本数减去2。因此命题正确。老师，我有点没明白，自由度是n-k-1，那不就是残差的，但是题目没说检测的是残差项呀
老师上课没有说耶 还是在哪边呀
