计量新手一个。在做实证时候遇到一个让我傻眼的问题。做出来的实证结果与假设相反。
. xtreg lndpi lnhrp lngdp lniop lnmt lnpfs,fe
Fixed-effects (within) regression Number of obs = 170
Group variable: city Number of groups = 17
R-sq: Obs per group:
within = 0.8473 min = 10
between = 0.6010 avg = 10.0
overall = 0.5349 max = 10
F(5,148) = 164.19
corr(u_i, Xb) = -0.8847 Prob > F = 0.0000
------------------------------------------------------------------------------
lndpi | Coef. Std. Err. t P>|t| [95% Conf. Interval]
-------------+----------------------------------------------------------------
lnhrp | -1.122719 .3434411 -3.27 0.001 -1.801401 -.4440377
lngdp | .4516046 .1037285 4.35 0.000 .2466245 .6565848
lniop | .3655639 .1080736 3.38 0.001 .1519972 .5791306
lnmt | -4.085603 .5497867 -7.43 0.000 -5.172049 -2.999157
lnpfs | .2987428 .0423741 7.05 0.000 .2150064 .3824791
_cons | 21.41269 2.40959 8.89 0.000 16.65104 26.17434
-------------+----------------------------------------------------------------
sigma_u | .6962411
sigma_e | .15713256
rho | .95153398 (fraction of variance due to u_i)
------------------------------------------------------------------------------
F test that all u_i=0: F(16, 148) = 10.29 Prob > F = 0.0000
上面为回归结果。被解释变量为LNdpi,为保险密度;解释变量为lniop ,为文盲率。假设是lniop的下降会导致lndpi的上升。
即文盲率的下降会导致保险密度的上升。查阅过文献,教育程度的上升会提高保险率。所以假设应该是文盲率下降,
保险密度上升。lniop的值系数应该是负值但是根据回归结果来看,与解释完全相反。
数据处理过程没有错误,回归结果来看,p值也蛮符合。但是为什么与假设完全相反?有大神能给个合理解释么?
到底哪里出错了