回归稀释偏倚

X变量如果有度量误差或者噪音的话，斜率估计就会偏小。X的方差越大，偏离的越多。如果可能的话，应该尽量避免出现这种问题。

Regression dilution, also known as regression attenuation, is the biasing of the regression slope towards zero (or the underestimation of its absolute value), caused by errors in the independent variable.