求助大神,我做公司融资决策的面板数据的实证分析,把自变量定为实际控制人与总经理的关系,re0代表实际控制人为实际控制人本人,re1代表总经理为实际控制人亲人,re2代表总经理为实际控制人的熟人,re3代表总经理与实际控制人为生人,要删除其中一个自变量不然会有多重共线性,所以要删除哪个自变量呢?有什么依据吗?为什么删除不同的自变量,回归结构都不一样?
第一个是删除了re3做的固定效应回归
Fixed-effects (within) regression Number of obs = 3,902
Group variable: id Number of groups = 1,109
R-sq: Obs per group:
within = 0.1767 min = 1
between = 0.3209 avg = 3.5
overall = 0.3053 max = 4
F(7,2786) = 85.44
corr(u_i, Xb) = 0.0687 Prob > F = 0.0000
------------------------------------------------------------------------------
lev | Coef. Std. Err. t P>|t| [95% Conf. Interval]
-------------+----------------------------------------------------------------
re0 | -.0618584 .0130897 -4.73 0.000 -.0875249 -.0361919
re1 | -.0653961 .0177643 -3.68 0.000 -.1002287 -.0305636
re2 | -.0523587 .0125691 -4.17 0.000 -.0770044 -.027713
gender | .0092865 .0129759 0.72 0.474 -.0161568 .0347298
educat | -.0026734 .0044859 -0.60 0.551 -.0114693 .0061226
comsc | .1077086 .0049737 21.66 0.000 .097956 .1174612
growth | -.001678 .0043118 -0.39 0.697 -.0101327 .0067767
_cons | -1.900306 .1077937 -17.63 0.000 -2.11167 -1.688943
-------------+----------------------------------------------------------------
sigma_u | .15711242
sigma_e | .06516233
rho | .85322973 (fraction of variance due to u_i)
------------------------------------------------------------------------------
F test that all u_i=0: F(1108, 2786) = 20.54 Prob > F = 0.0000
第二个是删除了re0做的固定效应回归
Fixed-effects (within) regression Number of obs = 3,902
Group variable: id Number of groups = 1,109
R-sq: Obs per group:
within = 0.1767 min = 1
between = 0.3209 avg = 3.5
overall = 0.3053 max = 4
F(7,2786) = 85.44
corr(u_i, Xb) = 0.0687 Prob > F = 0.0000
------------------------------------------------------------------------------
lev | Coef. Std. Err. t P>|t| [95% Conf. Interval]
-------------+----------------------------------------------------------------
re1 | -.0035378 .0141689 -0.25 0.803 -.0313204 .0242448
re2 | .0094997 .0079558 1.19 0.233 -.0061003 .0250996
re3 | .0618584 .0130897 4.73 0.000 .0361919 .0875249
gender | .0092865 .0129759 0.72 0.474 -.0161568 .0347298
educat | -.0026734 .0044859 -0.60 0.551 -.0114693 .0061226
comsc | .1077086 .0049737 21.66 0.000 .097956 .1174612
growth | -.001678 .0043118 -0.39 0.697 -.0101327 .0067767
_cons | -1.962164 .1066753 -18.39 0.000 -2.171335 -1.752994
-------------+----------------------------------------------------------------
sigma_u | .15711242
sigma_e | .06516233
rho | .85322973 (fraction of variance due to u_i)
------------------------------------------------------------------------------
F test that all u_i=0: F(1108, 2786) = 20.54 Prob > F = 0.0000
为什么re前面的系数符号变了?
急,写毕业论文时才学的stata,现在差不多要定稿了,好多不懂的,求大神帮忙