# invchisq: Combine p values using inverse chi squared method In metap: Meta-Analysis of Significance Values

 invchisq R Documentation

## Combine p values using inverse chi squared method

### Description

Combine \mjseqnp-values by the inverse chi-squared method, also known as Lancaster's method\loadmathjax

### Usage

invchisq(p, k, data = NULL, subset = NULL, na.action = na.fail, log.p = FALSE)
## S3 method for class 'invchisq'
print(x, ...)


### Arguments

 p \sigvec k A vector of degrees of freedom to use, see details data Optional data frame containing variables subset Optional vector of logicals to specify a subset of the \mjseqnp-values na.action A function indicating what should happen when data contains NAs log.p \logp x An object of class ‘invchisq’ ... Other arguments to be passed through

### Details

Defined as \mjdeqn\sum_i=1^n \chi^2_k_i(p_i) > \chi^2_\sumk_i(\alpha)\sum \chi^2_k(p) > \chi^2_\sumk(\alpha)

If k is a single value it is used for all the p of which there are n. If any value of \mjseqnk_i\le0 then the corresponding \mjseqnp_i is not included.

\ltle

two

\plotmethod \nocancel

### Value

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

 chisq Value of chi-squared statistic df Associated degrees of freedom p Associated p-value validp The input vector with the illegal values removed

Michael Dewey

### References

\insertRef

becker94metap

\insertRef

lancaster49metap

See also sumlog and plotp
data(dat.metap)
beckerp <- dat.metap$beckerp invchisq(beckerp, 2) # same as sumlog invchisq(c(0.999, 0.999, 0.001, 0.001), 4) all.equal(exp(invchisq(beckerp, 2, log.p = TRUE)$p), invchisq(beckerp, 2)\$p)