Cohen's dpop
|
σ (population) |
Independent groups, use in power analyses when population σ is known, σ calculated with n
|
Cohen's ds
|
Pooled SD
|
Independent groups, use in power analyses when population σ is unknown, σ calculated with n-1 |
Hedges' g
|
Pooled SD
|
Independent groups, corrects for bias in small samples, report for use in meta-analyses |
Glass's Δ |
SD pre measurement or control condition |
Independent groups, use when experimental manipulation might affect the SD
|
Hedges' gav
|
(SD1 + SD2)/2 |
Correlated groups, report for use in meta-analyses (generally recommended over Hedges' grm) |
Hedges' grm
|
SD difference scores corrected for correlation |
Correlated groups, report for use in meta-analyses (more conservative then Hedges' gav) |
Cohen's dz
|
SD difference scores |
Correlated groups, use in power analyses |