A-Level Computer Science: Big Data & AI Revision

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What is the time complexity of binary search?

Big Data & AI is a core part of A-Level Computer Science. Revise the key concepts and common mistakes below, then lock them in with the free games.

Key concepts

OverfittingWhen a model fits training data too closely and fails on new data.

UnderfittingWhen a model is too simple to capture patterns in the data.

Training SetData used to fit a model.

Test SetHeld-out data used only for final evaluation.

Decision TreeA model that splits data on feature thresholds at each node.

Cross-ValidationSplitting data into folds to estimate generalisation.

PerceptronThe simplest neural unit — a weighted sum passed through a step function.

Neural NetworkLayers of neurons computing increasingly abstract features.

Where Big Data & AI sits in each exam board's specification. Tap a board to see what it lists.

AQABig dataSpec 7517

Learn Big Data & AI step by step

Free interactive mini-lessons: short screens, worked examples and quick checks. Pick your exam board:

Other boards:OCR

Questions where students often pick the tempting wrong answer — make sure you know the right one:

What is the time complexity of binary search?✗ O(n) - because it searches through items. ✓ O(log n).

A decision tree splits at each node on:✗ A random rule ✓ A feature threshold

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