power_Geometric {PASSED}

Power Calculation for Comparing Two Geometric Rates.

Description

Compute sample size or power for comparing two geometric rates.

Usage

power_Geometric(n1 = NULL, n2 = NULL, power = NULL, sig.level = 0.05,
mu1 = NULL, mu2 = NULL, duration = 1, equal.sample = TRUE, 
alternative = c("two.sided", "one.sided"), approach = 3)

Arguments

n1

sample size in group 1, or sample size in each group if equal.sample = TRUE

n2

sample size in group 2

power

power of test (1 minus Type II error probability)

sig.level

significance level (Type I error probability)

mu1

expected rate of events per time unit for group 1

mu2

expected rate of events per time unit for group 2

duration

(average) treatment duration

equal.sample

equal sample sizes for two groups, see details

alternative

one- or two-sided test

approach

1, 2, or 3; see Zhu and Lakkis (2014).

Details

Exactly one of the parameters n1, n2, and power must be passed as NULL, and that parameter is determined from the others.

If equal.sample = TRUE is used, N in output will denote the number in each group.

Since the geometric distribution is a special case of negative binomial distribution, we used the algorithm for negative binomial distribution with setting theta = 1. See power.nb.test for more details.

Value

Object of class "power.htest", a list of the arguments (including the computed one) augmented with note and method elements.

Examples

# calculate power, equal sizes
power_Geometric(n1 = 100, mu1 = 0.3, mu2 = 0.6)
# calculate power, unequal sizes
power_Geometric(n1 = 180, n2 = 140, mu1 = 0.3, mu2 = 0.5)
# calculate n
power_Geometric( mu1 = 0.3, mu2 = 0.4, power = 0.8)