extraneous variable

基本解释

Again, no extraneous or random variables can enter into the equation.
再次申明，外部的和随机的变数不能干扰这个过程。
More bias likely from extraneous variables, due to greater difficulty of controlling all aspects of experiment outside the laboratory.
可能会有来自额外变量的更多的偏差，因为在实验室外控制实验的所有方面有很大困难。
Wary of these possible criticisms, Rule and Ambady conducted a second experiment that controlled for such extraneous variables as self-presentation and hairstyle.
处于对这些批评的谨慎， Rule 和 Ambady实施了第二次实验以控制外部变量，例如自我表现和发型。