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Statistical Experiments · Part 1 of 3
3 exam-style questions with model answers, plus 3 quick multi-choice questions — every question on this part of the standard, grouped by the 1 page of notes they come from.
Write a full answer before you reveal the model one. That comparison is where the learning happens.
A researcher randomly gives half of 40 volunteers a caffeine drink and half a caffeine-free drink, then measures their reaction times. State the explanatory variable and the response variable.
Explain why the caffeine study is an experiment and not an observational study, and why that matters for the conclusion.
A newspaper reports that people who drink coffee have faster reaction times, based on surveying coffee drinkers and non-drinkers. Explain why this cannot show that coffee causes faster reactions, and how an experiment would fix it.