Problem
Professor Bertha Bettina conducted a research project exploring adolescent girl peer group pressure. She used closed-ended questionnaires and focus groups. Of the 221 girls that fit the criteria for inclusion, 90 girls agreed to complete the self-administered questionnaire; of those, 50 girls agreed to participate in focus groups. During analysis, descriptive statistics about behaviours reported by the girls were joined with major themes that came out of the focus group interviews. Which types of sampling designs did Professor Bettina use?