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Methods Guide

IID Methods

Percentile

Standard quantile-based CI. Simple but can have poor coverage for skewed distributions.

Basic (Reverse Percentile)

\[CI = [2\hat{\theta} - q_{1-\alpha/2},\; 2\hat{\theta} - q_{\alpha/2}]\]

BCa (Bias-Corrected and Accelerated)

The recommended default. Corrects for bias and skewness using jackknife acceleration:

\[\hat{a} = \frac{\sum_{i=1}^{n}(\hat{\theta}_{(\cdot)} - \hat{\theta}_{(i)})^3}{6\left[\sum_{i=1}^{n}(\hat{\theta}_{(\cdot)} - \hat{\theta}_{(i)})^2\right]^{3/2}}\]

Studentized (Bootstrap-t)

Uses pivotal quantity \(t^* = (\hat{\theta}^* - \hat{\theta}) / \hat{se}^*\) with nested bootstrap for SE.

Poisson Bootstrap

Weighted resampling with \(W \sim \text{Poisson}(1)\). Ideal for streaming/online algorithms.

Bernoulli Bootstrap

Binary weights \(W \sim \text{Bernoulli}(p)\). Useful for specific ML applications.

Subsampling (m-out-of-n)

Sampling without replacement, size \(m < n\). Required for non-regular statistics (max, min).


Time Series Methods

Moving Block Bootstrap (MBB)

Overlapping fixed-length blocks. Set block_length based on autocorrelation structure.

Circular Block Bootstrap (CBB)

Wraps data circularly to eliminate edge effects. Same block logic as MBB.

Stationary Bootstrap (Politis & Romano)

Random block lengths \(L \sim \text{Geometric}(1/\bar{L})\) where \(\bar{L}\) = mean_block.

Tapered Block Bootstrap

Applies a tapering window (Tukey, Hanning, etc.) to each block. For spectral density estimation.

AR-Sieve Bootstrap

Fits AR(p) model → extracts residuals → resamples residuals → reconstructs series.

Wild Bootstrap

$\(y_t^* = \hat{y}_t + \hat{\varepsilon}_t \cdot v_t\)$ where \(v_t\) is Rademacher (±1) or Mammen two-point. Handles heteroskedasticity.


Hierarchical Methods

Cluster Bootstrap

Resamples entire clusters (groups), preserving within-group correlation structure.

Stratified Bootstrap

Resamples within each stratum independently, preserving class proportions.