R: Combine p values using logit method

logitp {metap} | R Documentation

## Combine p values using logit method

### Description

Combine p values using logit method

### Usage

    logitp(p)
    ## S3 method for class 'logitp'
    print(x, ...)

### Arguments

`p` | A vector of p values
`x` | An object of class ‘`logitp`’
`...` | Other arguments to be passed through

### Details

Defined as

t = - sum log(p / (1 - p)) / C

where

C = sqrt((k pi^2 (5 k + 2)) / (3(5 k + 4)))

and k is the number of studies.

The values of p should be such that 0<p<1. A warning is issued if this means that studies are omitted and an error results if as a result fewer than two studies remain.

The plot method for class ‘`metap`’ calls `schweder` on the valid p-values

### Value

An object of class ‘`logitp`’ and ‘`metap`’, a list with entries

`t` | Value of Student's t
`df` | Associated degrees of freedom
`p` | Associated p-value
`validp` | The input vector with illegal values removed

### Author(s)

Michael Dewey

### References

Becker, B J. Combining significance levels. In Cooper, H and Hedges, L V, editors A handbook of research synthesis, chapter 15, pages 215–230. Russell Sage, New York, 1994.

### See Also

See also `schweder`

### Examples

    data(teachexpect)
    logitp(teachexpect) # t = 2.763, df = 99, p = 0.0034, from Becker
    data(beckerp)
    logitp(beckerp) # t = 1.62, df = 29, NS, from Becker
    data(validity)
    logitp(validity) # t = 9.521, df = 104, p = 3.89 * 10^{-16}

[Package metap version 0.8 Index]