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GCSE Mathematics · key term
Choosing an item and not returning it before the next choice, so the items available for the next choice change.
Used by AQA, Edexcel and OCR
Specification N5 · Paper 1, Paper 2, Paper 3
Choosing an item without returning it before the next choice, so fewer options remain.
Revise: Systematic ListingIf choices are made without replacement, an item cannot be chosen again, so the number of available choices decreases.
Specification P9 · Paper 1, Paper 2, Paper 3
For draws without replacement, update both the number of items of each type and the total before labelling the second branches.
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A selection in which the chosen item is not returned, so later probabilities can change.
If a bag initially contains 5 red and 3 blue counters and two counters are selected without replacement, then after a red counter is selected there are 4 red counters among 7 remaining.
Specification 11.02d · Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Foundation), Paper 4 (Higher), Paper 5 (Higher), Paper 6 (Higher)
Revise: Tree DiagramsFor a draw without replacement, check what remains after the first outcome before completing the next branches. Finally, read along each full path to make sure your tree lists every possible sequence.