Hedge's g reports the difference between two group means in pooled-standard-deviation units, then applies a small-sample correction.
That makes it a good compact effect-size companion to a t-test, especially when sample sizes are modest.
A positive value means group 1 is larger on average. A negative value means group 2 is larger.
Rules like are only rough guides; domain context still matters.
Effortlessly calculate Cohen's d effect size online to quantify the difference between two group means.
Perform a one-sample z-test to determine if there is a statistically significant difference between a sample mean and a known population mean.
Perform Analysis of Variance (ANOVA) online to compare means of multiple groups.