Define and frame
Rewrite “Group C is more effective” as a descriptive research question answerable with these data. Specify the observational unit.
Scenario: The A/B/C labels of 36 fictional people represent neither interventions nor random assignment. What comparison is defensible before designing a real study?
Use the fictional dataset if the question refers to it. Always show your reasoning; an exact number without context is not enough. The four written tasks are teacher-assessed. The self-check below is formative and does not affect the 20-mark assignment.
Written problem set
Calculate or apply
Define random sampling and random assignment separately. Which may support generalisation and which may support causal inference?
Evaluate the design
If motivation affects both study time and scores, name its role and explain why measuring it may matter.
Interpret and communicate
Explain how to report a preregistered primary hypothesis versus an exploratory hypothesis generated after inspecting data.
Standard scoring guide
Each written task is worth 5 points: correct key idea (2), justified application or computation (2), and a clear statement with limits (1). This original rubric is not official UCL assessment.
Formative self-check · 4 questions
Choose one answer for each item, then check the feedback. Answers and explanations are available on this public study page; the separate written-task instructor key is private.