z* = critical value (1.645 for 90%, 1.96 for 95%, 2.576 for 99%)
Margin of error measures the precision of a sample estimate compared to the true population value.
⚠For proportions, p̂=0.5 gives maximum MOE. Use p̂=0.5 when unknown for conservative estimate.
What is Margin of Error?
Margin of error (MOE) is a measure of the amount of random sampling error in a survey's results. A larger margin of error indicates less confidence that the sample results accurately reflect the true population parameters.
SurveysPollsMarket ResearchStatisticsQuality Control
Frequently Asked Questions
What is margin of error?▼
Margin of error (MOE) is the amount of random sampling error in survey results. It indicates how much the sample estimate might differ from the true population value.
What is a good margin of error?▼
MOE under 5% is generally considered good for most surveys. Lower MOE requires larger sample size. Acceptable MOE depends on research requirements.
How sample size affects MOE?▼
Larger sample size reduces MOE. MOE is inversely proportional to the square root of sample size (n). Doubling n reduces MOE by about 30%.
Why use 95% confidence level?▼
95% is standard convention in statistics. It means we are 95% confident the true value lies within the confidence interval (sample estimate ± MOE).
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