1. What is Eta Squared Effect Size?

Eta squared (η²) is an effect size measure used in ANOVA that represents the proportion of variance in the dependent variable that is explained by the independent variable. It ranges from 0 to 1, with higher values indicating a stronger effect.

2. How Does the Calculator Work?

The calculator uses the eta squared formula:

Where:

• \( SS_{effect} \) — Sum of squares for the effect (between groups)
• \( SS_{total} \) — Total sum of squares

Explanation: The equation calculates the proportion of total variance attributable to the experimental effect or group differences.

3. Importance of Eta Squared Calculation

Details: Eta squared provides valuable information about the practical significance of research findings, complementing statistical significance tests. It helps researchers understand the magnitude of effects observed in their studies.

4. Using the Calculator

Tips: Enter both sum of squares values (must be positive numbers). SS_effect cannot exceed SS_total. Values are unitless as eta squared is a proportion.

5. Frequently Asked Questions (FAQ)

Q1: What is considered a small, medium, or large eta squared value?
A: Generally, η² = 0.01 is small, 0.06 is medium, and 0.14 is large, though interpretation depends on research context.

Q2: How does eta squared differ from partial eta squared?
A: Eta squared includes all variance in the denominator, while partial eta squared removes variance from other factors in the model.

Q3: When should I use eta squared?
A: Eta squared is appropriate for one-way ANOVA designs and when you want to report the proportion of total variance explained.

Q4: Are there limitations to eta squared?
A: Eta squared can be biased in small samples and tends to overestimate the population effect size. It's also sample-size dependent.

Q5: Can eta squared be negative?
A: No, eta squared values range from 0 to 1 as it represents a proportion of variance explained.