hi every body. i have a question from you:

I first run a probit regression. In this regression, all variables are dummy variables (binary) variables.
Then I get the margins of all variables when two explanatory variables are in the value of 1 (beside on the following code.)
These two explanatory variables are i.L2underline and i.Lunderline.
What is the interpretation of the i.L2underline coefficient?
In other words What is the interpretation of .3406954؟؟




code of stata:

. probit underline i.Lq i.Lunderline i.L2q i.L2underline [pw=Weight]

Iteration 0: log pseudolikelihood = -4148965.2
Iteration 1: log pseudolikelihood = -2930488
Iteration 2: log pseudolikelihood = -2919236.4
Iteration 3: log pseudolikelihood = -2919231
Iteration 4: log pseudolikelihood = -2919231

Probit regression Number of obs = 20,174
Wald chi2(4) = 2340.87
Prob > chi2 = 0.0000
Log pseudolikelihood = -2919231 Pseudo R2 = 0.2964

-------------------------------------------------------------------------------
| Robust
underline | Coef. Std. Err. z P>|z| [95% Conf. Interval]
--------------+----------------------------------------------------------------
1.Lq | .2236635 .0531638 4.21 0.000 .1194644 .3278627
1.Lunderline | 1.19886 .0436968 27.44 0.000 1.113215 1.284504
1.L2q | .1820238 .054248 3.36 0.001 .0756998 .2883479
1.L2underline | .890711 .0461142 19.32 0.000 .8003288 .9810932
_cons | -1.656304 .0233418 -70.96 0.000 -1.702053 -1.610555
-------------------------------------------------------------------------------

. margins, dydx(_all) at(L2underline=1 Lunderline=1)

Average marginal effects Number of obs = 20,174
Model VCE : Robust

Expression : Pr(underline), predict()
dy/dx w.r.t. : 1.Lq 1.Lunderline 1.L2q 1.L2underline
at : Lunderline = 1
L2underline = 1

-------------------------------------------------------------------------------
| Delta-method
| dy/dx Std. Err. z P>|z| [95% Conf. Interval]
--------------+----------------------------------------------------------------
1.Lq | .0753659 .0175447 4.30 0.000 .0409789 .1097529
1.Lunderline | .4457022 .0146431 30.44 0.000 .4170022 .4744022
1.L2q | .0618543 .0181925 3.40 0.001 .0261978 .0975109
1.L2underline | .3406954 .016691 20.41 0.000 .3079815 .3734092
-------------------------------------------------------------------------------
Note: dy/dx for factor levels is the discrete change from the base level.