Marginal effect of interaction variable in probit regression using Stata -
i running probit regression interaction between 1 continuous , 1 dummy variable. coefficient displayed in regression output when @ marginal effects interaction missing.
how can marginal effect of interaction variable?
probit move_right c.real_income_change_percent##i.gender iteration 0: log likelihood = -345.57292 iteration 1: log likelihood = -339.10962 iteration 2: log likelihood = -339.10565 iteration 3: log likelihood = -339.10565 probit regression number of obs = 958 lr chi2(3) = 12.93 prob > chi2 = 0.0048 log likelihood = -339.10565 pseudo r2 = 0.0187 ----------------------------------------------------------------------------------------------------- move_right | coef. std. err. z p>|z| [95% conf. interval] ------------------------------------+---------------------------------------------------------------- real_income_change_percent | .0034604 .0010125 3.42 0.001 .001476 .0054448 | gender | female | .0695646 .1139538 0.61 0.542 -.1537807 .2929099 | gender#c.real_income_change_percent | female | -.0039908 .0015254 -2.62 0.009 -.0069805 -.0010011 | _cons | -1.263463 .0798439 -15.82 0.000 -1.419954 -1.106972 ----------------------------------------------------------------------------------------------------- margins, dydx(*) post average marginal effects number of obs = 958 model vce : oim expression : pr(move_right), predict() dy/dx w.r.t. : real_income_change_percent 1.gender -------------------------------------------------------------------------------------------- | delta-method | dy/dx std. err. z p>|z| [95% conf. interval] ---------------------------+---------------------------------------------------------------- real_income_change_percent | .0002846 .0001454 1.96 0.050 -4.15e-07 .0005697 | gender | female | -.0102626 .0207666 -0.49 0.621 -.0509643 .0304392 -------------------------------------------------------------------------------------------- note: dy/dx factor levels discrete change base level.
your question seems strange me. asked dummy-dummy interaction, example involves continuous-dummy interaction.
here's how either one:
webuse union, clear /* dummy-dummy iteraction */ probit union i.south##i.black grade, nolog margins r.south#r.black /* continuous-dummy iteraction */ probit union i.south##c.grade margins r.south, dydx(grade) you should try reproduce these "hand" (using differences of predicts) understand margins command doing behind scenes.
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