DataTerminology.comNEW
Also known as: Random Error
The difference between a sample statistic and its corresponding population parameter due to random sampling variability.
DESCRIPTION
Sampling error reflects the natural variability that occurs when drawing a sample instead of observing an entire population. It decreases with larger sample sizes and lower population variability. Standard error quantifies average sampling error across many samples. Unlike bias, sampling error is random and can be reduced by design and size, but never eliminated entirely without a census. Distinguishing sampling error from non-sampling errors is crucial for sound inference.
ALTERNATIVE DEFINITIONS
Encyclopaedia Britannica
Sampling error, in statistics, the difference between a sample statistic and a corresponding population parameter that arises because only a sample is observed.
Clarifies cause: observing a sample rather than population.
NIST/SEMATECH e-Handbook of Statistical Methods
Sampling error is the error caused by observing a sample instead of the whole population.
Frames sampling error within process of data collection and variation.
RELATED TERMS
Sampling Bias Standard Error Margin of Error Confidence Interval Variance Random Sampling Selection Bias Measurement Error Central Limit Theorem
COMPETING TERMS
Non-sampling Error
KNOWLEDGE AREAS
Mathematics Data Science Testing & Validation
TARGET AUDIENCE
Data Scientist Data Analyst Information Analyst
EXTERNAL SOURCES
- Wikipedia - Sampling error
- OpenStax - Intro section explaining sampling error context
- NIST - Handbook discussion on sampling error
- Penn State STAT 200 - Course notes on sampling and errors
TOP QUESTIONS
How is Sampling Error different from Bias?
Sampling error is random variation from using a sample; bias is systematic deviation. Good design reduces bias, while larger samples reduce sampling error.
Category: Misunderstanding
How can I reduce Sampling Error?
Increase sample size and ensure representative sampling. Use stratification to reduce variability within groups.
Category: Best practices
Does Sampling Error disappear with large samples?
It diminishes but never fully vanishes unless you conduct a census. Standard error decreases as sample size grows.
Category: Opinion
Why does Sampling Error matter in surveys?
It sets the margin of error for estimates, informing how precise your survey results are.
Category: Relevancy
How is Sampling Error quantified?
Typically by the standard error of a statistic, derived from variance and sample size assumptions.
Category: Requirements
What is a common mistake regarding Sampling Error?
Attributing discrepancies to sampling error when non-sampling errors like measurement mistakes or bias are actually to blame.
Category: Mistakes
How does stratified sampling affect Sampling Error?
Stratifying homogeneous groups often reduces sampling error, improving estimate precision.
Category: Example
Is Sampling Error relevant in A/B testing?
Yes. It determines the variability of measured effects and the confidence in winners.
Category: Application
What is the risk of ignoring Sampling Error?
Overconfident conclusions and underpowered studies, which can lead to poor decisions.
Category: Risks