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Statistics · FRQ Trainer

Free-response 1 of 26 · Inference for Quantitative Data: Means

6 pts our rubric

The real Statistics Section II is 4 free-response questions in 90 minutes, 50% of your score. Redesigned for 2026-27: four questions — two multi-focus questions, one inference question (hypothesis test or confidence interval), and one multi-focus question spanning practices 2-4. Parts are still scored essentially/partially/incorrect rather than by adding rubric rows. (Through 2026 the exam ran six questions ending in the Investigative Task.) This prompt is ours, written to the same skills — score it against the rubric below, not against that structure.

Prompt

A researcher tests whether a new fertilizer increases mean tomato yield. She randomly assigns 40 plants to two groups of 20. New: x̄₁ = 5.4 kg, s₁ = 1.2. Standard: x̄₂ = 4.7 kg, s₂ = 1.1.

aState the hypotheses.1 pt

bName the test and check conditions.2 pts

cThe test gives t = 1.92, df ≈ 37, p = 0.031. State a conclusion at α = 0.05 in context.2 pts

dExplain what a Type I error would be here.1 pt

Keep writing to unlock scoring (0/120)

Write your response first — then grade it with AI or self-score against the rubric.