ssutil (version 1.0.0)

sim_power_nbinom: Empirical Power for Negative Binomial Comparison

Description

Estimates empirical power to detect a relative risk either above or below a specified boundary, depending on the direction of the alternative hypothesis. Simulates count data with over dispersion, fits a model with glm.nb, and evaluates the power to reject the null hypothesis using a negative binomial model.

Usage

sim_power_nbinom(
  n1,
  n2,
  ir1,
  tm,
  rr,
  boundary,
  dispersion,
  alpha,
  nsim,
  conf.level = 0.95
)

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.

Arguments

n1

Integer. Number of participants in group 1.

n2

Integer. Number of participants in group 2.

ir1

Numeric. Incidence rate in group 1.

tm

Numeric. Average exposure time per subject (assumed equal across subjects).

rr

Numeric. True relative risk between groups (group 2 rate = rr × group 1 rate).

boundary

Numeric. Relative risk boundary under the null hypothesis.

dispersion

Numeric. Dispersion parameter (\(\phi\)) for the negative binomial distribution.

alpha

Numeric. Type I error rate (two-sided).

nsim

Integer. Number of simulation iterations.

conf.level

Numeric. Confidence level for the empirical power estimate

Author

Chris Gast

John J. Aponte

See Also

empirical_power_result

Examples

# \donttest{
sim_power_nbinom(
 n1 = 150, n2 = 150,
 ir1 = 0.55, tm = 1.7,
 rr = 0.6, boundary = 1,
 dispersion = 2,
 alpha = 0.05,
 nsim = 1000
)
# }