SAT Math: Margin of Error vs Sample Size
25+ practice questions in Praczo
The concept, explained
- 1
Margin of Error (MoE) indicates the uncertainty in survey results based on only taking a sample of the population.
- 2
The size of the MoE is INVERSELY proportional to the sample size.
- 3
This means if you INCREASING the number of people surveyed, you DECREASE the margin of error (the data becomes more reliable/tighter).
- 4
The SAT will not ask you to calculate the MoE formula; just understand the directional relationship between sample size and error.
- ✗ Assuming a larger sample size produces a larger margin of error.
- ✗ Thinking margin of error measures "mistakes" made by the researchers rather than statistical sampling variance.
SAT-style practice
A polling firm repeats a survey on mayoral candidates. Survey A polls 500 people, yielding a 4% margin of error. Survey B polls 2,000 people. Which statement about Survey B's margin of error is most likely true?
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