Final answer:
Cross-sectional studies collect data at a single point from different populations to observe outcomes or behaviors. Data can be gathered via questionnaires and be both qualitative and quantitative. This method helps compare different group characteristics without the time costs of longitudinal studies.
Step-by-step explanation:
A cross-sectional study is an observational study where data is collected from a diverse sample of subjects at a single point in time. This methodology allows researchers to compare different population segments simultaneously. For example, if exploring dietary habits, a researcher may compare groups of people by age groups, such as 20-year-olds, 30-year-olds, and 40-year-olds, to analyze dietary differences without the need for a longitudinal, time-consuming study.
Often, data for cross-sectional studies are gathered through questionnaires with closed-ended questions that subjects respond to. This type of instrument is effective for collecting both quantitative data, which is numerical and easily analyzed statistically, and qualitative data, reflecting people's behaviors and opinions.
Considering the example of collecting data on video game usage among different age cohorts, researchers would sample different groups, administer the study, and gather data categorically, transforming it into countable and analyzable forms.