Loading…
Loading…
GCSE Mathematics · key term
A systematic effect in the way a sample is selected or data is collected that makes some outcomes or members more likely to be represented than others.
Used by AQA, Edexcel and OCR
Specification S1, S5 · Paper 1, Paper 2, Paper 3
A systematic distortion caused when some members of the population are more likely to be selected or represented than others.
Revise: Population InferenceA larger sample can reduce random variation, but an improved selection method is needed to reduce bias.
A systematic effect that makes the collected data unrepresentative of the population.
Specification S1 · Paper 1, Paper 2, Paper 3
A systematic influence that makes some members or outcomes more likely to be included than others and may distort a conclusion.
Revise: Populations and SamplesBias occurs when the selection method systematically favours some members of the population. Its likely effect should be explained rather than merely described as “biased”.
Specification 12.01a · Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Foundation), Paper 4 (Higher), Paper 5 (Higher), Paper 6 (Higher)
Revise: Populations and SamplesRandom selection reduces selection bias, but it does not guarantee that one particular sample will perfectly match the population. A genuinely random sample can be unrepresentative purely by chance. This random variation is different from bias: variation changes unpredictably from sample to sample, whereas bias repeatedly pushes results in a particular direction.
A larger sample generally reduces sampling variation, but it cannot remove bias caused by a poor selection method.
Create a free account to read GCSE Mathematics revision notes for your exam board and track your progress.