Description Usage Arguments Value Author(s) See Also

This is an auxiliary function. It calculates the type I error rate and the power of the design with an internal pilot study for different timings of the pilot study and for multiple actual differences in expected differences. The originally planned sample size is calculated on the basis of an assumed standard deviation. A distinction is made between one-sided and two-sided tests.

1 2 |

`delta` |
Number. Expectation difference of two samples. |

`Delta` |
Number/ Vector of numbers. Relevant difference of expected values in the alternative hypothesis. |

`sd` |
Number. Assumed standard deviation of the data. |

`test` |
Number. What type of hypothesis test should be performed. One-sided (Superiority/ |

`alpha` |
Number. Desired alpha-level of the test. |

`beta` |
Number. Acceptable beta error of the test. |

`prop` |
Number/ sequence of numbers. |

`adj` |
Logical. Should the one-sample variance, calculated in the internal pilot study, be adjusted? |

`rule` |
Logical. Should the sample size adjustment rule be applied by Wittes and Brittain? |

`nbound` |
Number. Upper limit of the sample size. |

`simu` |
Number. How many simulations should be performed? |

This function only creates the power values for multiple timings of the internal pilot studies.

The output is used in the function `pow_prop`

to visualize the power depending on the

timing for different true expected value differences.

Csilla van Lunteren

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