Mathematics
The Bootstrap Method for Estimating Sampling Distributions
Quick fact
The bootstrap method lets you estimate the sampling distribution of almost any statistic by resampling from your original data thousands of times—without needing to know the population's distribution or derive complex formulas.
Why this is interesting
You have a dataset and want to know how much your sample statistic might vary if you repeated the experiment—but you can only run the experiment once. What can you do?