Description Usage Arguments Details Value Author(s) References Examples

Computes power for genotypic TDT, allelic TDT or Score test given n trios or required sample size to gain given power.

1 2 3 4 5 |

`maf` |
a numeric vector of population frequencies of a mutant allele. |

`RR` |
a numeric vector of the assumed relative risks for an individual getting a disease with 1 (in case of recessive model 2) mutant alleles compared to the risk of individuals carnying 0 mutant alleles. |

`alpha` |
a numeric vector of significance levels (Type I Error probability). |

`n` |
a numeric vector containing number of trios in a study. Must be filled for power calculation. Must not be NULL for sample size calculation. |

`beta` |
the desired power of the test. Must be filled for power calculation. Must not be NULL for sample size calculation. |

`model` |
a character containing the genotypic model assumed. Possible values are |

`test` |
the chosen test. Must be |

`x` |
an object of class |

`digits` |
number of digits that should be printed. |

`...` |
ignored |

Power and sample size calculation is derived on Knapp (1999). The power or the sample size will be calculated for all combinations of p, RR, alpha, test, model and n or beta.

An object of class trio.power containing the following numeric values or vectors, respectively:

`model` |
the chosen model |

`size` |
In case of sample size calculation: calculated sample sizes |

`beta` |
In case of sample size calculation: desired power |

`n` |
In case of power calculation: given number of trios |

`power` |
In case of power calculation: calculated power |

`alpha` |
Type I error |

`test` |
the chosen test |

`RR` |
the relative risks assumed |

`p` |
the assumed allele frequency |

`calc` |
the type of calculation |

Christoph Neumann

Knapp, M. (1999). A Note on Power Approximations for the Transmission/Disequilibrium Test. *American Journal of Human Genetics*, 64, 1177-1185.

Neumann, C., Taub, M.A., Younkin, S.G., Beaty, T.H., Ruczinski, I., Schwender, H. (2014). Analytic Power and Sample Size Calculation for the Genotypic Transmission/Disequilibrium Test in Case-Parent Trio Studies. Submitted.

1 2 3 4 5 6 | ```
# The required samples size to reach of power
# of 0.8 when testing SNPs with minor allele
# frequencies of 0.1 and 0.2 with an additive
# or dominant genotypic TDT and score test
# can be determined by
trio.power(maf = c(0.1, 0.2), beta = 0.8, model = c("add", "dom"))
``` |

```
Trio studies sample size calculation
Test Model MAF alpha RR beta Trios
1 gTDT additive 0.1 5e-08 1.5 0.8 2524
2 gTDT additive 0.2 5e-08 1.5 0.8 1607
3 gTDT dominant 0.1 5e-08 1.5 0.8 2771
4 gTDT dominant 0.2 5e-08 1.5 0.8 1950
5 Score additive 0.1 5e-08 1.5 0.8 2505
6 Score additive 0.2 5e-08 1.5 0.8 1596
7 Score dominant 0.1 5e-08 1.5 0.8 2749
8 Score dominant 0.2 5e-08 1.5 0.8 1935
9 aTDT multiplicative 0.1 5e-08 1.5 0.8 2505
10 aTDT multiplicative 0.2 5e-08 1.5 0.8 1596
```

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