Bootstrapping is a technique for finding confidence intervals
directly by resampling. The first histogram shows the original
sample. The second histogram is the resample drawn from the
original sample with replacement. The third histogram is the
bootstrap (or resampling) distribution of the statistic
calculated from the resamples. Above the third histogram is the
bootstrap percentile confidence interval (the central 95% of the
bootstrap distribution). In all the histograms the bin height is
the fraction of values in that bin. The one-population data is
from 72 monthly totals of accidental deaths in the United
States. The two-populations data is from body weights in kg of
97 male and 47 female cats. For the two-populations example the
third histogram compares the two groups by calculating for each
pair of resamples the difference between the statistic applied
to the resample of the male cats minus the statistic applied to
the resample of the female cats. Both datasets are from the
example data included with Ma