Eta Squared (η²) Calculator — ANOVA Effect Size — GetCalcMaster

What this calculator is

The Statistics Calculator is an interactive tool inside GetCalcMaster. It’s designed to help you explore scenarios, understand formulas, and document assumptions.

Key features

• Supports η² and partial η² definitions
• Works directly from sums of squares (SS) output
• Clarifies the difference between η² and partial η²

Formula

η² = SS_effect / SS_total
partial η² = SS_effect / (SS_effect + SS_error)

Quick examples

• If SS_effect=20 and SS_total=100 → η²=0.20 (20% of total variance explained).
• If SS_effect=20 and SS_error=80 → partial η²=20/(20+80)=0.20.

Verification tips

• η² and partial η² must be between 0 and 1.
• If SS_effect increases while SS_total fixed, η² increases.

Common mistakes

• Mixing η² and partial η² in the same report without labeling them.
• Assuming partial η² values can be compared across different models without context.

How to use it (quick steps)

1. From your ANOVA output, collect the relevant sums of squares.
2. Compute η² = SS_between / SS_total (or SS_effect / SS_total for an effect).
3. Compute partial η² = SS_effect / (SS_effect + SS_error) when appropriate.
4. Report the chosen metric and be explicit about which one you used.

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FAQ

Tip: For reproducible work, save your inputs and reasoning in Notebook.