Code:
sysuse nlsw88,clear
reg married i.collgrad##c.wage
margins collgrad, at(wage== (5 10 15)) post
. margins collgrad, at(wage== (5 10 15)) post
Adjusted predictions Number of obs = 2,246
Model VCE : OLS
Expression : Linear prediction, predict()
1._at : wage = 5
2._at : wage = 10
3._at : wage = 15
Delta-method
Margin Std. Err. t P>t [95% Conf. Interval]
_at#collgrad
1#not college grad .6452051 .0123095 52.42 0.000 .6210659 .6693443
1#college grad .6846007 .0275997 24.80 0.000 .630477 .7387244
2#not college grad .6331711 .0134103 47.22 0.000 .6068732 .6594691
2#college grad .6502325 .020849 31.19 0.000 .6093471 .6911179
3#not college grad .6211372 .0211735 29.34 0.000 .5796154 .6626589
3#college grad .6158643 .0254564 24.19 0.000 .5659437 .6657849
display e(b)[1,2] / e(b)[1,1]
display e(b)[1,4] / e(b)[1,3]
display e(b)[1,6] / e(b)[1,5]
I'm using Stata 16.1.
