Probability
The mathematics of uncertainty and chance.
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The Language of Chance
You have measured the physical world with geometry and trigonometry. Now let us measure uncertainty itself.
Imagine a remote control that tells you the future — not as a video, but as a percentage. Probability is the math of working out those percentages before the event happens.
Key idea
You'll measure single events on a 0-to-1 scale, use past data to predict the future, and map branching paths — the secret code behind weather forecasts, insurance, and board games.
Memory trick
Probability is just 'Winners divided by Everyone'.
What You Will Learn
You will start with a single event on a 0-to-1 scale, then combine events, and finish by tracing branching paths where one outcome changes the next.
Steps
- 1
Basic probability: listing outcomes and putting a single event on the scale.
- 2
Probability from Venn diagrams, tables and charts.
- 3
Relative frequency and expectation: using past data to predict what happens next.
- 4
Combined events with two-way tables.
- 5
Tree diagrams, first for independent events and then for dependent ones.
Formula
On a tree diagram: multiply along the branches, add between them. That single habit answers most of the marks in this topic.
Practise probability now
Interactive visual aids, then real past-paper questions marked on your working like the exam. Free to start.
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