我看manual里面说的是：
1. do the logit estimation and get the output
2. click on "Proc" - "Forecast"
3. click on "Index - where Prob = 1-F(-Index)"
4. click on "Proc" and "Make Residual Series" - create a name for a series of data
5. then I get a series of data
6. take the average of that series of data in step 5
scalar xb= @mean(forecast value of dependent variable)

7. then estimate the following scalar
scalar l_xb = @dlogistic(-xb)
8. then multiply scalar l_xb to each coefficient to get marginal effect

已解决