ci_mean: CI for the Population Mean

Description

This function calculates CIs for the population mean. By default, Student's t method is used. Alternatively, Wald and bootstrap CIs are available.

Usage

ci_mean(
  x,
  probs = c(0.025, 0.975),
  type = c("t", "Wald", "bootstrap"),
  boot_type = c("stud", "bca", "perc", "norm", "basic"),
  R = 9999L,
  seed = NULL,
  ...
)

Value

An object of class "cint" containing these components:

parameter: Parameter specification.
interval: CI for the parameter.
estimate: Parameter estimate.
probs: Lower and upper probabilities.
type: Type of interval.
info: Additional description.

Arguments

x: A numeric vector.
probs: Lower and upper probabilities, by default c(0.025, 0.975).
type: Type of CI. One of "t" (default), "Wald", or "bootstrap".
boot_type: Type of bootstrap CI ("stud", "bca", "perc", "norm", "basic"). Only used for type = "bootstrap".
R: The number of bootstrap resamples. Only used for type = "bootstrap".
seed: An integer random seed. Only used for type = "bootstrap".
...: Further arguments passed to boot::boot().

Details

Bootstrap CIs are calculated by the package "boot", see references. The default bootstrap type for the mean is "stud" (bootstrap t) as it enjoys the property of being second order accurate and has a stable variance estimator (see Efron, p. 188).

References

Smithson, M. (2003). Confidence intervals. Series: Quantitative Applications in the Social Sciences. New York, NY: Sage Publications.
Efron, B. and Tibshirani R. J. (1994). An Introduction to the Bootstrap. Chapman & Hall/CRC.
Canty, A and Ripley B. (2019). boot: Bootstrap R (S-Plus) Functions.

Examples

Run this code

x <- 1:100
ci_mean(x)
ci_mean(x, type = "bootstrap", R = 999, seed = 1)  # Use larger R

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