pwr4exp

The pwr4exp package is an R package that provides functions for power calculation and sample size determination in animal experiments. The package emphasizes the importance of specifying models for conducting power analyses and supports power analyses for main effects, interactions, and specific contrasts. Additionally, pwr4exp offers a flexible framework to perform power analysis on customized designs which are currently not predefined in the package.

Installation

You can install the development version of pwr4exp from GitHub with:

devtools::install_github("WangKai7kkw/pwr4exp")

#Load the package
browseVignettes("pwr4exp")

Functions

Performing power analysis in pwr4exp involves the following steps:

• First, create a desired design object using design generating functions.
• Once the design object is created, calculating power or determining sample size using pwr4exp is straightforward. Simply pass the design object to the power calculator for main effects and interactions, pwr.anova(), or for contrasts, pwr.contrast().
• To determine the minimal sample size to achieve a target power, a quoted design object can be passed to the function find_sample_size().

Example Usage

Here's an example of how you can generate a design and calculate power:

library(pwr4exp)
# Define a design
crd <- designRCBD(
  treatments = c(2, 2),
  label = list(facA = c("A1", "A2"), facB = c("B1", "B2")),
  blocks = 10,
  formula = y ~ facA*facB + (1|block),
  beta = c(470, 30, -55, 5),
  VarCov = 3200,
  sigma2 = 3200
)

# Calculate power of ominubus test (i.e., F-test)
pwr.anova(design = crd)

# Calculate power for contrasts
pwr.contrast(design = crd, specs = ~ facB | facA, contrast = "pairwise")

Learn More

To learn more about pwr4exp, read through the vignette for pwr4exp which contains:

• Details on how to provide required inputs.
• Examples of conducting power analysis on the standard designs available in the package.
• Examples of using pwr4exp to assess the power of a customized design.

Additionally, more information is available at the package website.

The documentation for this package is being updated. If you have any questions or suggestions, please feel free to contact the package maintainer.