Description Usage Arguments Value Author(s) References See Also Examples

View source: R/N.cohen.kappa.R

This function is a sample size estimator for the Cohen's Kappa statistic for a binary outcome. Note that any value of "kappa under null" in the interval [0,1] is acceptable (i.e. k0=0 is a valid null hypothesis).

1 2 | ```
N.cohen.kappa(rate1, rate2, k1, k0, alpha=0.05,
power=0.8, twosided=FALSE)
``` |

`rate1` |
the probability that the first rater will record a positive diagnosis |

`rate2` |
the probability that the second rater will record a positive diagnosis |

`k1` |
the true Cohen's Kappa statistic |

`k0` |
the value of kappa under the null hypothesis |

`alpha` |
type I error of test |

`power` |
the desired power to detect the difference between true kappa and hypothetical kappa |

`twosided` |
TRUE if test is two-sided |

returns required sample size

Ian Fellows

Cantor, A. B. (1996) Sample-size calculation for Cohen's kappa. Psychological Methods, 1, 150-153.

1 2 3 | ```
# Testing H0: kappa = 0.7 vs. HA: kappa > 0.7 given that
# kappa = 0.85 and both raters classify 50% of subjects as positive.
N.cohen.kappa(0.5, 0.5, 0.7, 0.85)
``` |

```
Loading required package: lpSolve
[1] 96
```

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