Bootstrap and Resampling
Estimate uncertainty by resampling data.
Key idea
Estimate uncertainty by resampling data.
In depth
Draw many samples with replacement from your data to estimate the variability of a statistic without formulas. The spread of the bootstrap statistics approximates the sampling distribution.
Worked example
Resample 1,000 times, compute each median, and use the 2.5th and 97.5th percentiles as a confidence interval.
Real-world uses
- Estimating how uncertain a median or a score is when the data is not normal
Common mistake
Using it on tiny or unrepresentative samples; it cannot create information.
How to learn this
- Read the key idea and say it in your own words.
- Work through the worked example, then try a similar problem.
- Use the interactive lesson’s visual and mini-quiz to check the pattern.
Frequently asked questions
What is Bootstrap and Resampling?
Estimate uncertainty by resampling data. It is a topic at the expert level in Probability & Statistics.
Where is Bootstrap and Resampling used in real life?
Real-world examples: Estimating how uncertain a median or a score is when the data is not normal.
What should I learn before Bootstrap and Resampling?
Make sure you are comfortable with Bayesian Inference, the previous topic in Probability & Statistics.
What is a common mistake with Bootstrap and Resampling?
Using it on tiny or unrepresentative samples; it cannot create information.
How can I practise Bootstrap and Resampling?
Open the interactive lesson, play with the visual, then answer the three-question mini-quiz. Getting two right marks the topic complete.
What comes after Bootstrap and Resampling?
Move on to Monte Carlo Simulation next.
Related expert topics in Probability & Statistics
- Skewness and Kurtosis – Measures of asymmetry and tail heaviness.
- Residuals and R² – Error of a fit and proportion of variance explained.
- Simpson’s Paradox – A trend reverses when groups are combined.
- Law of Total Probability – Split an event over a partition.
- Bayes’ Theorem – Update beliefs with evidence.
- Medical Tests and Base Rates – Why positive results can still be probably false.