The goal of the analysis is to find a correlation between birth context and stature, while controlling for age.
Each person has an ID number, age, stature, and birth context. That last part is what is giving me trouble. There are three type of birth context: foreign, which means they were born in another country, immigrant, which means they were born within 9 years of their mother moving to the US, and established, which means that they were born after 10 years of the mother being in the US.
I'm not sure how to control for age in this situation. Would I have to make separate dummy variables for each age, such as age 10, in the established group?
Anything that points me in the right direction is appreciated.