To cite package ‘experiment’ in publications use:

  Imai K, Jiang Z (2022). _experiment: R Package for Designing and
  Analyzing Randomized Experiments_. R package version 1.2.1,
  <https://CRAN.R-project.org/package=experiment>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {experiment: R Package for Designing and Analyzing Randomized Experiments},
    author = {Kosuke Imai and Zhichao Jiang},
    year = {2022},
    note = {R package version 1.2.1},
    url = {https://CRAN.R-project.org/package=experiment},
  }