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Power to Correctly Select the Best Group in a Binomial Test

Source: R/ss_best_binomial.R
power_best_binomial.Rd

Computes the exact probability of correctly identifying the best group when the outcome follows a binomial distribution. It assumes that p1 is the probability of success in the best group, and that the success probability in all other groups is lower by a fixed difference dif.

Usage

power_best_binomial(p1, dif, ngroups, npergroup)

Arguments

p1

Numeric. Probability of success in the best group (must be in [0, 1]).

dif

Numeric. Difference in success probability between the best group and the next best (must be > 0).

ngroups

Integer. Number of groups (must be greater than 1).

npergroup

Integer. Number of subjects per group (must be positive).

Value

A numeric value representing the probability of correctly identifying the best group.

Details

The formula is based on the exact method described by Sobel and Huyett (1957).

References

Sobel, M., & Huyett, M. J. (1957). Selecting the Best One of Several Binomial Populations. Bell System Technical Journal, 36(2), 537–576. doi:10.1002/j.1538-7305.1957.tb02411.x

Examples

power_best_binomial(p1 = 0.8, dif = 0.2, ngroups = 4, npergroup = 50)
#> [1] 0.963308