mes2: Means with Pooled SD to Effect Size

Description

Converts raw mean scores (with pooled standard deviation reported) to an effect size of $d$ (mean difference), $g$ (unbiased estimate of $d$), $r$ (correlation coefficient), $z'$ (Fisher's $z$), and log odds ratio. The variances, confidence intervals and p-values of these estimates are also computed, along with NNT (number needed to treat), U3 (Cohen's $U_(3)$ overlapping proportions of distributions), CLES (Common Language Effect Size) and Cliff's Delta.

Usage

mes2(m.1, m.2, s.pooled, n.1, n.2, level=95, dig=2, id=NULL, data=NULL)

Arguments

m.1

Mean of group one.

m.2

Mean of group two.

s.pooled

Pooled standard deviation.

n.1

Sample size of group one.

n.2

Sample size of group two.

level

Confidence level. Default is 95%.

dig

Number of digits to display. Default is 2 digits.

Study identifier. Default is NULL, assuming a scalar is used as input. If input is a vector dataset (i.e., data.frame, with multiple values to be computed), enter the name of the study identifier here.

data

name of data.frame. Default is NULL, assuming a scalar is used as input. If input is a vector dataset (i.e., data.frame, with multiple values to be computed), enter the name of the data.frame here.

Value

dStandardized mean difference ($d$).
var.dVariance of $d$.
l.dlower confidence limits for $d$.
u.dupper confidence limits for $d$.
U3.dCohen's $U_(3)$, for $d$.
cl.dCommon Language Effect Size for $d$.
cliffs.dCliff's Delta for $d$.
p.dp-value for $d$.
gUnbiased estimate of $d$.
var.gVariance of $g$.
l.glower confidence limits for $g$.
u.gupper confidence limits for $g$.
U3.gCohen's $U_(3)$, for $g$.
cl.gCommon Language Effect Size for $g$.
p.gp-value for $g$.
rCorrelation coefficient.
var.rVariance of $r$.
l.rlower confidence limits for $r$.
u.rupper confidence limits for $r$.
p.rp-value for $r$.
zFisher's z ($z'$).
var.zVariance of $z'$.
l.zlower confidence limits for $z'$.
u.zupper confidence limits for $z'$.
p.zp-value for $z'$.
OROdds ratio.
l.orlower confidence limits for $OR$.
u.orupper confidence limits for $OR$.
p.orp-value for $OR$.
lORLog odds ratio.
var.lorVariance of log odds ratio.
l.lorlower confidence limits for $lOR$.
u.lorupper confidence limits for $lOR$.
p.lorp-value for $lOR$.
N.totalTotal sample size.
NNTNumber needed to treat.

References

Borenstein (2009). Effect sizes for continuous data. In H. Cooper, L. V. Hedges, & J. C. Valentine (Eds.), The handbook of research synthesis and meta analysis (pp. 279-293). New York: Russell Sage Foundation. Cohen, J. (1988). Statistical power for the behavioral sciences (2nd ed.). Hillsdale, NJ: Erlbaum. Furukawa, T. A., & Leucht, S. (2011). How to obtain NNT from Cohen's d: comparison of two methods. PloS one, 6(4), e19070. McGraw, K. O. & Wong, S. P. (1992). A common language effect size statistic. Psychological Bulletin, 111, 361-365. Valentine, J. C. & Cooper, H. (2003). Effect size substantive interpretation guidelines: Issues in the interpretation of effect sizes. Washington, DC: What Works Clearinghouse.

Description

Usage

Arguments

Value

References

See Also