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Bootstrap confidence interval for Cohen's d

Source: R/bootstrap_ci.R
cohens_d_ci.Rd

Percentile bootstrap for the standardised mean difference between two independent groups. Each resample draws within each group, preserving the group sizes.

Usage

cohens_d_ci(x, y, R = 2000, conf.level = 0.95, seed = NULL)

Arguments

x, y

Numeric vectors, one per group.

R

Integer. Number of bootstrap resamples. Defaults to 2000.

conf.level

Confidence level. Defaults to 0.95.

seed

Integer or NULL. When supplied, sets the random seed.

Value

A named numeric vector: estimate, lower, upper, with attributes resamples, valid_resamples and, when the interval is withheld, reason. The bounds are NA when fewer than 90% of resamples give a value, or when every resample gives the same value, since neither leaves a sampling distribution to read. The bounds are NA when either group has fewer than 3 finite values.

See also

bootstrap_ci()

Examples

cohens_d_ci(mtcars$mpg[mtcars$am == 1], mtcars$mpg[mtcars$am == 0],
            seed = 42)
#>  estimate     lower     upper 
#> 1.4779471 0.7869318 2.5256596 
#> attr(,"resamples")
#> [1] 2000
#> attr(,"valid_resamples")
#> [1] 2000