Dr. Choi is studying the extent to which Asian American mothers enforce gender roles at home. She wants to ensure that her sample includes 50 first generation, 50 second generation, and 50 third generation immigrants. If Dr. Choi obtains her particular sample by putting flyers in the local Asian grocery store, which of the following sampling techniques is she using?
Group of answer choices
snowball sampling
purposive sampling
quota sampling
stratified random sampling