ri.d: _d_-value (i.e., standardized mean difference) Replication...

In replicationInterval: Replication Interval Functions

Description

d-value (i.e., standardized mean difference) Replication Interval

Usage

ri.d(d, n1, n2, rep.n1 = NA, rep.n2 = NA, prob.level = 0.95)

Arguments

d	Original study: Sample d-value (standardized mean difference) created with pooled variance denominator. See formulas 4.18 and 4.19 (p.26) in Borenstein, Hedges, Higgins, & Rothstein (2009).
n1	Original study: Sample size for group 1
n2	Original study: Sample size for group 2
rep.n1	(optional) Replication study: Sample size for group 1. If not specified, n1 is used.
rep.n2	(optional) Replication study: Sample size for group 2. If not specified, n2 is used.
prob.level	(optional 0 to 1 value) Probability level desired (0 to 1). If not specified .95 (i.e., 95 percent) will be used.

Value

A list of values (lower.replication.interval.d, upper.replication.interval.d) containing the replication interval (and related statistics if requested with the extended.output argument).

References

Borenstein, M., Hedges, L. V., Higgins, J. P., & Rothstein, H. R. (2009). Introduction to meta-analysis. John Wiley & Sons.

Cumming, G., & Finch, S. (2001). A primer on the understanding, use, and calculation of confidence intervals that are based on central and noncentral distributions. Educational and Psychological Measurement, 61(4), 532-574.

Examples

ri.d(d=.65,n1=50,n2=50,rep.n1=100,rep.n2=100)

Example output

Original study: d = 0.65, N1 = 50, N2 = 50, 95% CI[0.25, 1.05]
Replication study: N1 = 100, N2 = 100
Replication interval: 95% RI[0.16,1.14].


Interpretation:
The original d-value is 0.65 - with a replication interval 95% RI[0.16, 1.14] based a replication cell sizes N1 = 100 and N2 = 100. If the replication d-value differs from the original d-value only due to sampling error, there is a 95% chance the replication result will fall in this interval. If the replication d-value falls outside of this range, factors beyond sampling error are likely also responsible for the difference.

replicationInterval documentation built on May 2, 2019, 3:35 p.m.