For an assignment I have to calculate the marginal effect of 'age' by hand. But I am dealing with a logit model, which makes it difficult for me. I have 4 variables, which are age, education, income and the price of cigarettes. The dependent variable is a dummy variable that indicates whether someone is a smoker, yes or no. I have been running regressions in Stata, since this is the main part of the assignment. Hence, I already have quite some information, such as the marginal effects at the mean and the average marginal effects.
Now the issue starts at the question where I cannot use Stata. I need to calculate the marginal effect of age by hand for a person with age = 28, education = 15, income = 12,500 and price of cigarettes = 60. Now these numbers do not really matter, but for completeness I have added them nonetheless. Where do I start with this? I think I need some of the already obtained data to perform my calculations. To be honest I am just clueless at this point.