Is this a cross-sectional study, a retrospective study, or a prospective study? Stratified Sampling The prices of generic items are compared to the prices of the equivalent named brand items. (hint: A cross-sectional study has been conducted when data is observed, measured, or collected at one point in time. A retrospective study has been conducted when data is collected from the past using records, interviews, and other similar artifacts. A prospective study has been conducted when data is collected in the future from groups sharing common factors.) O Prospective study Cross-sectional study O Retrospective study