SAT and ACT math terms · SAT Math, ACT Math
Margin of error
Margin of error: A range around a sample estimate within which the true population value is likely to fall, at a given confidence level.
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What it means
If a survey finds 52% support with a margin of error of 3 percentage points, the true value is plausibly between 49% and 55%. Larger random samples generally produce smaller margins of error.
Conclusions should only be generalized to the population from which the random sample was drawn.
Example
A random sample of 400 students estimates that 30% walk to school, with a margin of error of 4%. A plausible range for all students is 26% to 34%.
On the exam
SAT questions ask what a margin of error means and what conclusions a study supports.
Lessons and practice questions
Related terms
- Mean, median and modeMeasures of center: the mean is the average, the median is the middle value, and the mode is the most frequent value.
- Observational study vs. experimentAn experiment randomly assigns treatments and can show cause and effect; an observational study only observes and can show association.