pwr_sigma_2pop: Power and sample size for F test for variance.
In gilberto-sassi/power:

Description Usage Arguments Details Value Examples

pwr_sigma_2pop computes the power and the sample size for testing to compare variances of two normal population.

1 2	pwr_sigma_2pop(sigma1, sigma2, n1 = NULL, n2 = NULL, pwr = NULL, alternative = "two.sided", sig_level = 0.05)

`sigma1`	populational standard deviation for the first population
`sigma2`	populational standard deviation for the second population
`n1`	number of observations (sample size) for the first population
`n2`	number of observations (sample size) for the second population
`pwr`	power of test 1 + β (1 minus type II error probability)
`alternative`	a character string specifying the alternative hypothesis, must be one of "two.sided" (default), "greater" or "less"
`sig_level`	significance level (Type I error probability)

Exactly one of the parameters samples sizes ('n1' and 'n2') and 'pwr' must be passed as NULL, and that parameter is determined from the other. Notice that the last one has non-NULL default so NULL must be explicitly passed if you want to compute it.

The parameters 'sigma1 and 'sigma2' are required. The effect size is computed internally.

pwr_sigma_2pop returns a list with the following components:

sigma1: populational standard deviation
sigma2: standard deviation under null hypothesis
sig_level: significance level
power_sampleSize: A tibble with sample size, n1 for the first population and n2 for the second population

# Power
pwr_sigma_2pop(sigma1 = 10, sigma2 = 20, n1 = 25, n2 = 21, pwr = NULL,
alternative = "two.sided", sig_level = 0.05)
# Sample size
pwr_sigma_2pop(sigma = 10, sigma0 = 20, n = NULL, pwr = 0.95,
alternative = "two.sided", sig_level = 0.05)