# meanz: Combine p values using mean z method In metap: Meta-Analysis of Significance Values

 meanz R Documentation

## Combine p values using mean z method

### Description

Combines p values using the mean of z method\loadmathjax

### Usage

meanz(p, log.p = FALSE)
## S3 method for class 'meanz'
print(x, ...)


### Arguments

 p \sigvec log.p \logp x An object of class ‘meanz’ ... Other arguments to be passed through

### Details

Let \mjdeqn\barz = \sum_i=1^k \fracz(p_i)kbarz = sum(z(p) / k) and \mjdeqns_\barz = \fracs_z\sqrtks_barz = s_z / sqrt k Defined as \mjdeqn \frac\barzs_\barz > t_k-1(\alpha) ((barz / s_barz) > t_k-1(alpha)

\lele

two As can be seen if all the \mjseqnp_i are equal or close to equal this gives a \mjeqnt=\pm\inftyt=+-infty leading to a returned value of 0 or 1. A set of \mjseqnp values with small variance will necessarily give a small \mjseqnp value which may be smaller than that for another set all of whose primary values are less than any in the first set. See examples for a demonstration.

\plotmethod

### Value

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

 z The value of the mean \mjseqnz statistic p The associated \mjseqnp value validp The input vector with illegal values removed

Michael Dewey

### References

\insertRef

becker94metap

See also plotp
data(dat.metap)
beckerp <- dat.metap$beckerp meanz(beckerp) meanz(c(0.1, 0.2)) # greater than next example meanz(c(0.3, 0.31)) # less than above all.equal(exp(meanz(beckerp, log.p = TRUE)$p), meanz(beckerp)\$p)