Problem: Camila is a psychologist interested the relationship between the amount of lead that is found in the bloodstream of young children and their performance on intelligence tests. Camila selects a random sample of 1000 8-year-old children. She first takes a blood sample from each child and measures the amount of lead in their blood. She then has each child complete a standardized intelligence test.
What type of method did Camila use in her study? Group of answer choices experimental correlational meta-analysis case study extreme groups