Statalist:
I am fitting a logistic regression model using svy in Stata version 9. I am trying to use the subpop option to focus on only those adults 55 and older. However, in my logistic model I specifically want to look at the differences among age categories for participation in adult education (aepart) so I also have age categories (AgeCat7) as an independent variable. I have received messages on my output that indicate putting in age will cause problems. My questions are:
1. Below is my output, note _IAgeCat7_7 dropped due to collinearity. This is the category for anyone under 55 so it shouldn't have been in the model, but does this message indicate another problem?
2. I have also run the model with 6 category age just coding age F = 0.0000
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| Linearized
aepart | Odds Ratio Std. Err. t P>|t| [95% Conf. Interval]
-------------+----------------------------------------------------------------
_IAgeCat7_2 | 1.128364 .1712264 0.80 0.426 .8380377 1.519269
_IAgeCat7_3 | .8190012 .1358204 -1.20 0.229 .5917043 1.133612
_IAgeCat7_4 | .8138198 .1540807 -1.09 0.277 .5614976 1.179529
_IAgeCat7_5 | 1.050606 .2072118 0.25 0.802 .7137293 1.546486
_IAgeCat7_6 | .5036011 .0968218 -3.57 0.000 .3454723 .7341085
_IIncomequ~2 | 1.415502 .2227664 2.21 0.027 1.03976 1.927027
_IIncomequ~3 | 1.448079 .2233722 2.40 0.016 1.070219 1.959348
_IIncomequ~4 | 2.326815 .3547075 5.54 0.000 1.725774 3.137182
_IHIGHEDUC_2 | 2.016762 .3553085 3.98 0.000 1.427813 2.848643
_IHIGHEDUC_3 | 3.010628 .8260452 4.02 0.000 1.758229 5.15512
_IHIGHEDUC_4 | 4.172463 .7755193 7.69 0.000 2.89842 6.006532
employed | 2.189151 .2617844 6.55 0.000 1.731701 2.767443
female | 2.234095 .2508465 7.16 0.000 1.792729 2.784124
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