# limits.percentile: Bootstrap confidence intervals In resample: Resampling Functions

## Description

Bootstrap confidence intervals - percentile method or t interval.

## Usage

 ```1 2 3 4``` ```CI.percentile(x, probs = c(0.025, 0.975), expand = TRUE, ...) CI.t(x, probs = c(0.025, 0.975)) CI.bca(x, probs = c(0.025, 0.975), expand = TRUE, L = NULL, ...) CI.bootstrapT(x, probs = c(0.025, 0.975)) ```

## Arguments

 `x` a `bootstrap` or `bootstrap` object. `probs` probability values, between 0 and 1. The default vector `c(0.025, 0.975)` gives a 95% two-sided interval. `expand` logical, if `TRUE` then use modified percentiles for better small-sample accuracy. `...` additional arguments to pass to `quantile.resample` and `quantile`. `L` vector of length `n`, empirical influence function values. If not supplied this is computed using `jackknife`.

## Details

`CI.bootstrapT` assumes the first dimension of the statistic is an estimate, and the second is proportional to a SE for the estimate. E.g. for bootstrapping the mean, they could be the mean and s. This is subject to change.

`CI.bca` and `CI.bootstrapT` currently only support a single sample.

## Value

a matrix with one column for each value in `probs` and one row for each statistic.

## Author(s)

Tim Hesterberg [email protected],
http://www.timhesterberg.net/bootstrap

## References

This discusses the expanded percentile interval: Hesterberg, Tim (2014), What Teachers Should Know about the Bootstrap: Resampling in the Undergraduate Statistics Curriculum, http://arxiv.org/abs/1411.5279.

`bootstrap`, `bootstrap2`, `ExpandProbs` (for the expanded intervals).
 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13``` ```## Not run: # See full set of examples in resample-package, including different # ways to call all four functions depending on the structure of the data. data(Verizon) CLEC <- with(Verizon, Time[Group == "CLEC"]) bootC <- bootstrap(CLEC, mean, seed = 0) bootC2 <- bootstrap(CLEC, c(mean = mean(CLEC), sd = sd(CLEC)), seed = 0) CI.percentile(bootC) CI.t(bootC) CI.bca(bootC) CI.bootstrapT(bootC2) ## End(Not run) ```