CI for the Population Std

Source: R/ci_measures_of_scale.R

This function calculates CIs for the population standard deviation. They are derived from CIs for the variance by taking the square-root, see ci_var().

ci_sd(
  x,
  probs = c(0.025, 0.975),
  type = c("chi-squared", "bootstrap"),
  boot_type = c("bca", "perc", "stud", "norm", "basic"),
  R = 9999L,
  seed = NULL,
  ...
)

Arguments

x

A numeric vector.

probs

Lower and upper probabilities, by default c(0.025, 0.975).

type

Type of CI. One of "chi-squared" (default) or "bootstrap".

boot_type

Type of bootstrap CI. 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().

Value

An object of class "cint", see ci_mean() for details.

See also

ci_var()

Examples

x <- 1:100
ci_sd(x)
#> 
#> 	Two-sided 95% chi-squared confidence interval for the population
#> 	standard deviation
#> 
#> Sample estimate: 29.01149 
#> Confidence interval:
#>     2.5%    97.5% 
#> 25.47229 33.70193 
#> 
ci_sd(x, type = "bootstrap", R = 999)  # Use larger R
#> 
#> 	Two-sided 95% bootstrap confidence interval for the population standard
#> 	deviation based on 999 bootstrap replications and the bca method
#> 
#> Sample estimate: 29.01149 
#> Confidence interval:
#>     2.5%    97.5% 
#> 26.73032 31.95780 
#>