Effect Sizes

d = 0.2

Small effect for Cohen’s d

d = 0.5

Medium effect for Cohen’s d

d = 0.8 or greater

Large effect for Cohen’s d

η² = 0.01

Small effect for ETA squared

η² = 0.06

Medium effect for ETA squared

η² = 0.14 or greater

Large effect for ETA squared

β ≈ .10

Small effect for standardized regression coefficient

β ≈ .30

Medium effect for standardized regression coefficient

β ≥ .50

Large effect for standardized regression coefficient

R² = Above 75%

Very good for adjusted R squared

R² = 50-75%

Good for adjusted R squared

R² = 25-50%

Fair for adjusted R squared

R² = Below 25%

Poor for adjusted R squared

r ≈ .10

Weak correlation

r ≈ .30

Moderate correlation

r ≥ .50

Strong correlation

F ≈ 1 (around 1)

Variance between groups is similar to the variance within groups. This typically indicates that there's no significant difference between the groups, and the null hypothesis (that there's no difference) would likely be accepted.

F > 1 (1-3; 3-5)

Variance between groups is larger than the variance within groups. This suggests that the group means are more different from each other than the data points within each group are from their respective means. 1-3 means there’s a slight difference, and 3-5 means there’s a moderate difference.

F » 1 (5+ or 10+)

Strong possibility of a statistically significant difference between the group means. In this case, you would likely reject the null hypothesis.