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Rohit Ghumare dda194f840 fix(quiz): correct answer is always in the same position (slot B) (#381)
Every "Test Your Understanding" quiz placed the correct answer in option B.
Across the 2026 questions in 338 quiz files the correct answer sat at index 1
in 61.5% of cases (uniform would be ~25%), and 107 files had every answer at B,
making the quizzes guessable without reading them.

scripts/debias_quizzes.py rewrites each question's option order with a
deterministic, content-seeded permutation and updates the correct index to
follow the moved answer. It is idempotent: options are canonicalised to a sorted
base before permuting, so re-running produces byte-identical output. Questions
whose options reference each other by position ("all of the above", "both A and
B") are left untouched. The correct-answer value, the option set, and every
explanation are preserved exactly; only order and the index change.

Result: A 23.8% / B 26.3% / C 23.5% / D 26.4%.

The script doubles as a CI guard: `--check` exits non-zero if any quiz is not
de-biased, wired into the curriculum workflow so new lessons cannot regress.

Fixes #368
2026-08-01 14:24:15 +01:00

103 lines
4.0 KiB
JSON

{
"lesson": "21-nli-textual-entailment",
"title": "Natural Language Inference — Textual Entailment",
"questions": [
{
"stage": "pre",
"question": "What three labels does NLI assign to a (premise, hypothesis) pair?",
"options": [
"True / false / unknown",
"Cause / effect / unrelated",
"Entailment / contradiction / neutral",
"Positive / negative / neutral"
],
"correct": 2,
"explanation": "NLI is a 3-way classification over entailment, contradiction, and neutral."
},
{
"stage": "pre",
"question": "How is NLI used as a zero-shot text classifier?",
"options": [
"By prompting an LLM",
"Verbalize each candidate label as a hypothesis (e.g. 'This text is about sports') and pick the label with the highest entailment score",
"By computing TF-IDF",
"By averaging embeddings"
],
"correct": 1,
"explanation": "NLI-as-classifier turns labels into hypotheses; the model picks the max-entailment label."
},
{
"stage": "check",
"question": "Why is NLI a faithfulness check for RAG outputs?",
"options": [
"It is cheap",
"Checking whether the retrieved context entails each answer claim is exactly the formulation NLI was trained on",
"It is multilingual",
"It uses tokenizers"
],
"correct": 1,
"explanation": "Hallucination = answer claims not entailed by retrieved context; NLI directly measures entailment."
},
{
"stage": "check",
"question": "What does the hypothesis-only baseline expose?",
"options": [
"Tokenizer drift",
"Slow inference",
"Multilingual gaps",
"Datasets where the hypothesis alone (without the premise) is predictive of the label, signalling label leakage"
],
"correct": 3,
"explanation": "A high hypothesis-only score on SNLI revealed annotation artifacts; useful for debugging your data."
},
{
"stage": "check",
"question": "Which NLI model family tops 2026 leaderboards as the standard workhorse?",
"options": [
"DeBERTa-v3 variants fine-tuned on MNLI/FEVER/ANLI",
"Plain Word2Vec",
"GPT-2",
"fastText"
],
"correct": 0,
"explanation": "DeBERTa-v3 fine-tuned on MNLI and related corpora is the open NLI workhorse in 2026."
},
{
"stage": "post",
"question": "Why do sentence-level NLI models drop accuracy on document-length premises?",
"options": [
"They were trained on short premises and fail at multi-sentence and multi-hop inference; DocNLI-tuned models handle longer inputs",
"Larger inputs run slower",
"Cosine similarity decays",
"Documents trigger tokenizer drift"
],
"correct": 0,
"explanation": "Training distribution mismatch: single-sentence NLI models lose 20+ F1 on document-length inputs."
},
{
"stage": "post",
"question": "Why can zero-shot accuracy swing 10+ points based on the hypothesis template?",
"options": [
"Templates change the label set",
"Models are sensitive to phrasing; e.g. 'This text is about {label}' vs '{label}' alone shifts entailment probabilities",
"Templates change tokenizer behavior",
"Templates affect model weights"
],
"correct": 1,
"explanation": "Template wording materially shifts entailment scores; tune it on a small held-out set."
},
{
"stage": "post",
"question": "What is a safe limit to claim about NLI for hallucination detection?",
"options": [
"It reduces hallucination as a faithfulness signal but does not eliminate it; combine with retrieval recall and human review",
"It only works on English",
"It eliminates hallucination",
"It requires LLMs"
],
"correct": 0,
"explanation": "NLI is a useful signal but not a complete solution; pair with retrieval metrics and human spot-checks."
}
]
}