Empirical Power for Equivalence (Normal Outcomes)

Estimates the empirical power to detect equivalence among multiple groups assuming no true difference in normally distributed outcomes. Pairwise two-sample t-tests are used, and equivalence is declared if all confidence intervals for differences between group means lie entirely within the interval defined by llimit and ulimit.

Usage

sim_power_equivalence_normal(
  ngroups,
  npergroup,
  sd,
  llimit,
  ulimit,
  nsim,
  t_level = 0.95,
  conf.level = 0.95
)

Arguments

ngroups

Integer. Number of groups to compare

npergroup

Integer. Number of observations per group.

sd

Numeric. Standard deviation of the outcome distribution (common across groups).

llimit

Numeric. Lower equivalence limit.

ulimit

Numeric. Upper equivalence limit.

nsim

Integer. Number of simulations to perform.

t_level

Numeric. Confidence level used for the t-tests (e.g., 0.95 for 95% CI).

conf.level

Numeric. Confidence level for the empirical power estimate

Value

An S3 object of class empirical_power_result, which contains the estimated empirical power and its confidence interval. The object can be printed, formatted, or further processed using associated S3 methods. See also empirical_power_result.

Details

This function simulates data under the null hypothesis of no difference between groups and calculates the proportion of simulations in which all pairwise comparisons fall within the specified equivalence limits.

See also

empirical_power_result

Examples

#Equivalence testing for three groups with log-scale outcome
sim_power_equivalence_normal(
  ngroups = 3,
  npergroup = 172,
  sd = 0.403,
  llimit = log10(2/3),
  ulimit = log10(3/2),
  nsim = 1000,
  t_level = 0.95
)
#> Empirical Power Result
#> ----------------------- 
#> Power:       0.9160
#> 95% CI:      [0.8971, 0.9324]
#> Simulations: 1000