Statistics
Confusing Margin of Error with Confidence Level
Students treat the confidence level as the plus-or-minus amount around a sample estimate.
Quick check
Why students make it
Both numbers are often written next to a poll result, so students think they measure the same kind of uncertainty. The confidence level feels like an error size because it is a percent.
The rule done right
The margin of error is the amount added and subtracted from the estimate, such as [0m3[0m a0b in [0m52b [0m a0b [0m3b. The confidence level tells how reliable the method is in the long run, such as [0m95b confidence.
Related resources
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Statistics, Confidence Level vs Confidence Interval Infographic -
Confidence Intervals Infographic -
Statistics, Confidence Interval for a Mean Infographic -
Statistics, Confidence Interval for a Proportion Infographic -
Statistics, Confidence Intervals vs Hypothesis Tests Infographic - Margin of Error Reference Cheat Sheet
- Confidence Interval Master Reference Cheat Sheet
- Confidence Intervals One- and Two-Sample Cheat Sheet
- Hypothesis Testing & Confidence Intervals Cheat Sheet
- Sampling Distribution & Standard Error Cheat Sheet
- Statistics, Confidence Intervals and Margin of Error Worksheet
- Statistics, Confidence Intervals Worksheet
- Statistics, The Normal Distribution and Z-Scores Worksheet
- Statistics, Hypothesis Testing Worksheet
- Confidence Interval Calculator Tool
- Sampling Distribution Visualizer Tool
- Central Limit Theorem Simulator Tool
- Normal Distribution & Z-Score Explorer Tool
- Hypothesis Testing Calculator Tool
- Sampling & Randomization Lab Lab
- Central Limit Theorem & Sampling Distributions Lab Lab
- Bootstrap & Confidence Interval Lab Lab
- Hypothesis Testing Lab Lab
- Experimental Design & A/B Testing Lab Lab