# Two Bags, Three Probabilities

## Learning design
- Topic: sample spaces, equally likely outcomes, and simple probability.
- Outcome: enumerate all ordered digit pairs, identify favourable outcomes, and simplify each probability.
- Architecture: diagnostic quiz with interactive 3 by 4 sample space, event highlighting, fraction entry, hints, and feedback.
- Model: all 12 pairs are equally likely; number = 10 times Bag 1 digit plus Bag 2 digit.
- Accessibility: keyboard-operable controls, labelled inputs, table headers, text as well as colour cues, responsive layout, reduced motion.
- Teacher review: discuss equally likely outcomes and fraction simplification. Answers are a) 4/12 = 1/3; b) 6/12 = 1/2; c) 0/12 = 0.

## Analytics contract
Stable item IDs: divisible_by_3, multiple_of_4, odd_number. Attempts include response, expected response, correctness, mark, attempt, first and final response, revisions, hint use, misconception code/explanation, and relative time. Completion state includes score, item evidence, process summary, misconception counts, and a visible teacher report.

No state is sent on launch. The activity uses preserved window.storeState integration. Reset clears local attempt data and deliberately does not transmit empty marks that could restore cached values. Identity and raw keystrokes are not collected.

## Package
index.html is at ZIP root. Local xAPI libraries are copied unmodified from the maintained Integrator sample.