相关系数与回归系数可以是负值,是由于下列哪式可出现负值
A ∑(X-X)<img border="0" alt="" src="https://img.weimei168.com/uploads/upimg/20230104/12296558_0.gif"> B
∑(Y-Y)<img border="0" alt="" src="https://img.weimei168.com/uploads/upimg/20230104/12296558_0_1.gif"> C
∑XY-(∑X)(∑Y)/n D
∑Y<img border="0" alt="" src="https://img.weimei168.com/uploads/upimg/20230104/12296558_0_2.gif">-(∑Y)<img border="0" alt="" src="https://img.weimei168.com/uploads/upimg/20230104/12296558_0_3.gif">/n E
∑(X-X)<img border="0" alt="" src="https://img.weimei168.com/uploads/upimg/20230104/12296558_0_4.gif">/n