Description Usage Arguments Details Value Note Authors

Compute the power of a simple cluster randomized trial, or determine parameters to obtain a target power.

1 2 |

`alpha` |
The level of significance of the test, the probability of a Type I error. |

`power` |
The power of the test, 1 minus the probability of a Type II error. |

`m` |
The number of clusters per condition. It should be greater than 1. |

`n` |
The mean cluster size, or a vector of cluster sizes with
length equal to twice |

`d` |
The standardized effect size. |

`ICC` |
The intra-class correlation. |

`cv` |
The coefficient of variation. When |

`tol` |
Numerical tolerance used in root finding. The default provides at least four significant digits. |

Exactly one of `alpha`

, `power`

, `d`

, `ICC`

, `m`

,
`n`

, and `cv`

must be passed as `NULL`

. Note that
`alpha`

, `power`

, `d`

, and `cv`

have non-`NULL`

defaults, so if those are the parameters of interest they must be
explicitly passed as `NULL`

.

The computed argument.

'uniroot' is used to solve power equation for unknowns, so you may see errors from it, notably about inability to bracket the root when invalid arguments are given.

Jonathan Moyer ([email protected]), but this function is based on work by Peter Dalgaard (power.t.test) and Stephane Champely (pwr.t.test).

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