varr {psychometric}

Sample Size weighted variance

Description

Computes the weighted variance in correlations from a data object of the general format found in EnterMeta

Usage

varr(x)

Arguments

x

A matrix or data.frame with columns Rxy and n: see EnterMeta

Details

For a set of correlations for each study (i), varr is computed as: sum(Ni*(ri-rbar)^2)/sum(Ni) where, Ni is the sample size of study i and ri is the correlation in study i and rbar is the weighted mean correlation.

Value

Sample weighted variance in correlations: uncorrected for artifacts other than sampling error

Note

This is the variance in correlations across studies corrected for sampling error. It is also known as bare-bones meta-analysis.

Author(s)

Thomas D. Fletcher [e-mail]

References

Arthur, Jr., W., Bennett, Jr., W., and Huffcutt, A. I. (2001) Conducting Meta-analysis using SAS. Mahwah, NJ: Erlbaum.

Hunter, J.E. and Schmidt, F.L. (2004). Methods of meta-analysis: Correcting error and bias in research findings (2nd ed.). Thousand Oaks: Sage Publications.

Hunter, J.E., Schmidt, F.L., and Jackson, G.B. (1982). Meta-analysis: Cumulating research findings across studies. Beverly Hills: Sage Publications.

See Also

vare, rbar

Examples

# From Arthur et al
data(ABHt32)
varr(ABHt32)
# From Hunter et al
data(HSJt35)
varr(HSJt35)