Planning and collecting multivariate data

Task goals

• Distinguish between categorical and numerical variables and identify multivariate data involving multiple variables of both types.
• Formulate statistical questions that specify a population, identify relevant variables, and guide data collection.
• Compare and evaluate different sampling methods (random, stratified, convenience) and explain how each affects bias and representativeness.
• Identify sources of bias in data collection and design strategies to minimize or eliminate bias through appropriate sampling, study design, or data-collection procedures.
• Design simple observational studies and experiments, distinguishing between the two approaches and choosing the appropriate method for a research question.
• Explain the role of confounding variables, control groups, and random allocation in experimental design.
• Demonstrate how sample size and sampling variation relate to the reliability of conclusions drawn from data.
• Apply ethical reasoning to data-collection decisions, considering informed consent, privacy, voluntary participation, and fair treatment of participants.