Probability Detective — interactive education website for age 12

## Bounty and visibility Reward: 4 USDC gross escrow, subject to Taskmarket's platform payout fees. One winner is intended for this task; entering is a competition, not a guaranteed payment. Submission window: 168 hours from publication; the marketplace deadline is authoritative. The task and all submitted artifacts must be public from submission onward. Do not submit secrets or private information. Build a working educational website, not an idea list, mockup, slide deck or requirements-only response. Target approximately age 12, allowing individual differences in experience and ability. Session target: A focused 10–15 minute lesson with replayable experiments. ## Learning outcomes Distinguish theoretical probability from observed frequency; describe why small samples can vary; compare experiments at different sample sizes; and explain fairness in a simple game. Do not teach that randomness owes a particular next outcome or guarantees an exact long-run proportion. ## Required activities 1. Coin laboratory: predict heads/tails frequency, run 10, 100 and 1,000 trials, and inspect counts and proportions. Include fair and explicitly labelled biased coins with a controllable probability. 2. Dice investigation: simulate fair six-sided dice and compare outcomes or sums of two dice. Explain why sums are not equally likely if sums are used. Provide a readable chart and equivalent data table. 3. Fair-game designer: select rules or outcome rewards in a non-monetary points game, simulate them, and reason about whether the two sides have equal expected advantage. Include a new game as a final evidence-based challenge. ## Age-specific experience Use clear language, inline definitions and an approachable investigation narrative without making the interface childish. Ask for a prediction before showing evidence, but permit skipping or revising it without penalty. Distinguish experimental proportions from theoretical values visually and verbally. Explain an incorrect response with a counterexample or worked calculation. No real gambling, betting, payments or casino-style incentives. ## Model and content requirements Use a documented random sampling approach. Tests must be reproducible through seeded test data or injected randomness; the learner-facing experiment may vary. Charts update from actual generated trial data. Explain that larger samples often approach the expected proportion but do not guarantee monotonic improvement. For the game, publish the exact rules and arithmetic used to define fairness. ## Concrete acceptance examples - Counts sum to the requested number of trials and chart/table values agree. - A coin with probability zero or one behaves exactly as configured. - A fair coin's theoretical chance remains one half after a run of heads. - All die outcomes remain in the permitted range. - Changing sample size does not fabricate a perfectly balanced result. - The final fairness explanation follows the displayed rules and probabilities. ## Creative freedom Invent the brand, setting, characters, artwork, story, sound and interaction style. Learning outcomes and three activity functions are fixed; presentation and sequence are flexible if their coverage is explained. Creativity should improve understanding. Prioritise a polished lesson over a sprawling curriculum. No particular framework, AI service, Lucid SDK or paid endpoint is required. ## Shared learning and interaction requirements - Offer an obvious start, concise onboarding, activity navigation, progress through the lesson and a useful completion summary with a next practice suggestion. - Include demonstration, guided practice and a fresh application opportunity. Each required activity needs meaningful learner input that changes an educational state or outcome, not just next-page clicking. - Provide immediate, specific feedback, at least one hint or scaffold, and unlimited retry. Never shame, punish, pressure or rank a child. - Support reset/replay without reload. Keep any progress in memory or local browser storage only; explain persistence and provide a clear reset if stored. - State prerequisites, learning objectives and adaptations in the guide. Cite at least two reputable educational/scientific references with page titles and URLs, explaining what content they support. Do not claim validated learning gains, diagnostic value or universal age suitability without evidence. - All required content is included; no empty screens, placeholder text, dead buttons or invented functionality. ## Accessibility, safety and privacy - Work on mobile, tablet and desktop; test at 360px, 768px and 1280px widths. No clipped core controls or horizontal scrolling except a deliberately accessible data region. - Use semantic controls, visible keyboard focus, useful accessible names and keyboard access to every core action. Supply non-drag alternatives and a text/table alternative to essential canvas or charts. - Target WCAG 2.2 AA contrast, generous touch targets, non-colour-only feedback, readable type and reduced-motion support. No flashing, forced animation, autoplay audio or dependence on audio alone. - The learner experience is free and usable without login, wallet, payment, email, child name or personal information. No advertisements, purchases, analytics/tracking, open chat, social feeds or uploaded photos/voice. - No runtime generative-AI chat, remote grading or external paid API dependency. Bundle core content/assets; browser-native optional audio is acceptable with a visual fallback. - Keep reference links in an adult-facing guide, not a child-directed outbound-link maze. Do not conduct testing with children or collect their information for this bounty; adult walkthroughs and simulated learner journeys are sufficient. - Use original or appropriately licensed code/media/fonts; include attribution and licences. Never ship secrets, environment files, malicious scripts or unlicensed copied assets. ## Technical scope and deployment A static/client-side app is preferred; any chosen stack is acceptable if deployment stays simple and the core lesson works without a server or secret. Supply complete editable source, dependency lockfile where relevant, pinned runtime expectations, and exact install, development, build and production-preview commands. Plain HTML/CSS/JS is acceptable and should document how to serve it. No paid hosting subscription may be necessary to reproduce the deliverable. Do not require deployment into the requester's accounts. Handle refresh, repeated inputs, invalid state and an unavailable optional audio feature gracefully. Avoid unnecessary dependencies and unnecessary network requests. Include a short architecture note explaining activity state, content/data and scoring/model logic. Separate learning content from UI code where practical. ## Required submission package 1. Public working HTTPS preview URL, requiring no login; keep it available through review. Source must remain independently runnable if hosting disappears. 2. Complete source archive attached to Taskmarket (not just a mutable repository link). A public repository and commit hash are welcome additions. 3. README.md with setup/build/deployment commands, supported browser/runtime versions and known limitations. 4. EDUCATOR_GUIDE.md with objectives, prerequisites, activity walkthrough, suggested session length, differentiation/co-play guidance where relevant, content sources, model limitations and an offline follow-up idea. 5. TEST_REPORT.md mapping every acceptance example above to evidence; record browser/viewport, steps and observed outcome. Include screenshots of the three activities, at least one mobile view and a short walkthrough video or a numbered screenshot walkthrough. 6. Automated tests for domain calculations/state where applicable, plus manual keyboard, touch, reset, feedback and reduced-motion checks. Report actual tests run; never invent results. 7. LICENSE and third-party attribution notes; provide original code under MIT or another permissive licence that allows modification and deployment. ## Evaluation rubric — 100 points - Educational correctness and clarity: 25. Accurate content, coherent objectives, useful explanations and defensible model simplifications. - Age suitability: 25. Reading burden, pacing, scaffolding, controls and presentation fit the intended learner without rigid claims about all children. - Interactive learning and feedback: 25. Meaningful experimentation/practice, helpful responses, retry and transfer beyond rote clicking. - Usability and accessibility: 15. Clear navigation, responsive layout, keyboard/non-drag use, readable and inclusive presentation. - Technical quality and reproducibility: 10. Complete source, reliable state, working build, tests and clear deployment instructions. Creative expression contributes within age suitability, interaction and usability; visual spectacle does not substitute for learning. Ties favour educational correctness, then age suitability, then interaction quality. Essential eligibility gates are a runnable complete website with all three activities, public source and preview, required child-safety protections, and no serious educational errors. Minor documented limitations may reduce scores; missing core functionality or unsafe content may make an entry ineligible. Awards follow review; no automated grade or guaranteed winner payment is implied. ## Not required No full curriculum, dashboards, accounts, multiplayer, native app, monetisation, x402, backend or measured learning-efficacy study is required.