我的是非线性关系,
逐步回归的结果: AC是中介变量
(1) (2) (3)
VARIABLES csr ac csr
Mix 0.051*** 0.035*** 0.052***
(2.83) (4.74) (2.89)
Mix2 -0.052*** -0.019** -0.053***
(-2.77) (-2.46) (-2.80)
ac -0.035
(-1.51)
lev -0.085*** -0.065*** -0.088***
(-9.51) (-17.52) (-9.63)
BS 0.011 -0.007* 0.010
(1.20) (-1.79) (1.17)
outsize 0.000 0.000 0.000
(1.31) (0.78) (1.32)
age -0.007 -0.002 -0.008
(-1.53) (-0.84) (-1.54)
size 0.044*** -0.012*** 0.043***
(34.58) (-22.89) (33.47)
roa 1.193*** -0.218*** 1.185***
(37.78) (-16.72) (37.07)
growth -0.004 -0.013*** -0.004
(-1.14) (-9.30) (-1.27)
dual -0.003 0.002 -0.003
(-0.74) (1.21) (-0.72)
opinion 0.015* -0.036*** 0.013
(1.69) (-10.08) (1.54)
Constant -0.749*** 0.438*** -0.733***
(-20.54) (29.02) (-19.40)
Observations 11,117 11,117 11,117
R-squared 0.397 0.261 0.397
第三个回归结果就不显著了,但是Bootstrap检验结果间接效应是显著的,请问我的这个中介变量是显著的吗?应该怎么判断