我现在需要检验变量Z的中介效应。首先看X对Y的影响，得到X的回归系数显著为负
| MCR22 | Coef. | Std. Err. | t | P>t | [95% Conf. | Interval] |
| | | |
| fcyd | -.0179584 | .0047513 | -3.78 | 0.000 | -.0272764 | -.0086404 |
| fmlinc1 | .0009523 | .000234 | 4.07 | 0.000 | .0004934 | .0014111 |
| asset1 | 1.39e-06 | 4.25e-06 | 0.33 | 0.743 | -6.95e-06 | 9.73e-06 |
| fml2016_count | -.0067643 | .001534 | -4.41 | 0.000 | -.0097726 | -.0037559 |
| avr_age | -.0011974 | .0002021 | -5.92 | 0.000 | -.0015938 | -.0008009 |
| avr_edu | .006699 | .0006307 | 10.62 | 0.000 | .0054622 | .0079359 |
| area1 | .0187272 | .0059859 | 3.13 | 0.002 | .0069879 | .0304665 |
| area2 | .0169599 | .0065884 | 2.57 | 0.010 | .0040389 | .0298808 |
| area3 | .0242239 | .007279 | 3.33 | 0.001 | .0099485 | .0384993 |
| _cons | .1526772 | .0143844 | 10.61 | 0.000 | .1244669 | .1808875 |
再看X对Z的影响，得到X的回归系数显著为正
| fcyd | 6174.371 | 2493.242 | 2.48 | 0.013 | 1284.708 | 11064.03 |
| fmlinc1 | -34.15229 | 123.0134 | -0.28 | 0.781 | -275.4021 | 207.0975 |
| asset1 | 1.084659 | 2.236263 | 0.49 | 0.628 | -3.301026 | 5.470344 |
| fml2016_count | -1078.194 | 805.0404 | -1.34 | 0.181 | -2657.012 | 500.6249 |
| avr_age | 323.9893 | 106.1842 | 3.05 | 0.002 | 115.7444 | 532.2342 |
| avr_edu | 1001.881 | 331.3527 | 3.02 | 0.003 | 352.0433 | 1651.719 |
| area1 | -891.4848 | 3143.035 | -0.28 | 0.777 | -7055.501 | 5272.532 |
| area2 | 7796.815 | 3462.573 | 2.25 | 0.024 | 1006.13 | 14587.5 |
| area3 | 1685.602 | 3820.729 | 0.44 | 0.659 | -5807.485 | 9178.69 |
| _cons | -21183.85 | 7555.06 | -2.80 | 0.005 | -36000.58 | -6367.116 |
最后，同时把X和Z放进方程右边
| fcyd | -.0185972 | .0047426 | -3.92 | 0.000 | -.0278983 | -.009296 |
| fumuqinqijinghe | 3.03e-07 | 1.16e-07 | 2.62 | 0.009 | 7.60e-08 | 5.30e-07 |
| fmlinc1 | .0009597 | .0002332 | 4.12 | 0.000 | .0005024 | .001417 |
| asset1 | 1.23e-06 | 4.24e-06 | 0.29 | 0.771 | -7.08e-06 | 9.55e-06 |
| fml2016_count | -.0066012 | .0015295 | -4.32 | 0.000 | -.0096008 | -.0036017 |
| avr_age | -.001255 | .0002022 | -6.21 | 0.000 | -.0016516 | -.0008584 |
| avr_edu | .0066685 | .0006299 | 10.59 | 0.000 | .0054333 | .0079038 |
| area1 | .0187584 | .0059647 | 3.14 | 0.002 | .0070606 | .0304562 |
| area2 | .0159067 | .0065759 | 2.42 | 0.016 | .0030102 | .0288032 |
| area3 | .0235602 | .0072582 | 3.25 | 0.001 | .0093257 | .0377947 |
| _cons | .1553379 | .0143691 | 10.81 | 0.000 | .1271577 | .1835181 |
得出来X系数显著为负，符合假设。但是为什么Z的回归系数显著为正呢？这与研究假设前面的回归结果都不能符合。
请问这是什么为何？该如何解释？Z的中介效应成立吗？
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雷达卡
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