NO.PZ2020010801000005
问题如下:
The from regressing Y on X is the same as the of regressing X on Y. True or false?
解释:
True. The in a regression with a single explanatory variable is the squared sample correlation between X and Y.
老师,推导的红线不明白,方差是(Y估计-Y均值)^2求和后还要求均值呢,为什么只是平方和就直接等于Y的方差了?第二个红线也是,为什么只是求和就直接是X的方差了?