power.z.test {asbio} | R Documentation |

## Power analysis for a one sample z-test

### Description

A power analysis for a one sample *z*-test. The function requires `\alpha`

, `\sigma`

,
the effect size, the type of test (one tailed or two-tailed), and either power
(1 - `\beta`

) or *n* (sample size). If *n* is provided, then power is calculated. Conversely,
if one provides power, but not *n*, then the required *n* is calculated.

### Usage

```
power.z.test(sigma = 1, n = NULL, power = NULL, alpha = 0.05, effect = NULL,
test = c("two.tail", "one.tail"), strict = FALSE)
```

### Arguments

`sigma` |
The population standard deviation. |

`n` |
The sample size. Not required if |

`power` |
The desired power. Not required if |

`alpha` |
Probability of type I error. |

`effect` |
Effect size. |

`test` |
One of two choices: |

`strict` |
Causes the function to use a strict interpretation of power in a two-sided test.
If |

### Value

Returns a list

`sigma` |
The prescribed population variance. |

`n` |
The sample size. |

`power` |
The power. |

`alpha` |
The type I error probability. |

`test` |
The type of test prescribed. |

`effect` |
The effect size. |

### Author(s)

Ken Aho

### References

Bain, L. J., and M. Engelhardt (1992) *Introduction to Probability and Mathematical
Statistics*. Duxbury press. Belmont, CA, USA.

### See Also

### Examples

```
power.z.test(sigma=6,effect=5,power=.9,test="one.tail")
```

*asbio*version 1.9-7 Index]