ClinSigMeasures (version 1.2)

cohens_d: Cohen's d Calculation

Description

Calculates a Cohen's d effect size using the means and standard deviations of two independent groups

Usage

cohens_d(Group1_Mean, Group1_SD, Group2_Mean, Group2_SD)

Value

A single value representing the Cohen's d effect size

Arguments

Group1_Mean

Mean for Group 1

Group1_SD

Standard Deviation for Group 1

Group2_Mean

Mean for Group 2

Group2_SD

Standard Deviation for Group 2

Author

Mike Malek-Ahmadi

References

1. Cohen, Jacob (1988). Statistical Power Analysis for the Behavioral Sciences. Routledge. ISBN 978-1-134-74270-7.

2. Malek-Ahmadi M, Perez SE, Chen K, Mufson EJ. Neuritic and diffuse plaque associations with memory in non-cognitively impaired elderly. J Alzheimers Dis 2016;53(4):1641-1652.

Examples

#From Table 2 in Malek-Ahmadi et al (2016)
#comparing groups with (0.75+/-0.35) and without (0.49+/-0.29) neuritic plaques
#on a global cognitive score (z-score).

cohens_d(0.75, 0.35, 0.49, 0.29)