The influncc of some uncontrolled factors must be consided in variance analysis. In this paper, the authors expounded covariance analysis with two correlated variables and solved it with quadric form.

• 进行方差分析，需要消除一些不可控因素的影响，这些因素有时以变量的形式出现，称为协变量。利用二次型解决了双协变量的方差分析方法。