NO.PZ2018101001000012
问题如下：
Mixcell does the regression analysis of X and Y and gets the following results:
Given the n is 52, which of the following conclusions is most likely correct?
选项：
A. X has a negative influence on Y.
B. Intercept Coefficient is not significant at the 5% level.
C. X is significant at the 5% level.
解释：
C is correct.
考点: Regression Coefficient: T-test.
解析: 当df=n-2=50 α=5%时, 查表可得, 此时的分界点为2.009，均小于intercept和X的t-Statistic,所以both X and intercept coefficient are significant at the 5% level，C正确，B错误。由表可知，slope即X的coefficient为4.5698，为positive，所以X has a positive influence on Y，A错误。
老师可否总结下自由度使用规律，已经被n n-1 n-k-1搞晕掉了