IGCSE Maths / Probability

Tree diagrams without replacement revision notes

Edexcel International GCSE Maths (4MA1), chapter 20: Probability, specification point 6.3a. Part of the full course.

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When counters are taken without replacement, the second pick is from a smaller group, so its probabilities change. Use a tree diagram to multiply probabilities along a path and add the paths that match the outcome.

More lessons in Probability

• The language of probability and the probability scale
• Listing outcomes systematically
• Theoretical probability and sample space
• Relative frequency and mutually exclusive events
• Expected frequency and relative frequency
• Multiplying independent probabilities
• At least one, and the complement
• Tree diagrams with replacement
• Three stage tree diagrams
• Probability problem solving
• Conditional probability from a two way table
• Conditional probability from a Venn diagram
• Conditional probability without replacement
• Forming an equation from a probability