ANOVA Calculator

Run a one-way ANOVA on three group summaries.

F-statistic 7.219
df between 2
df within 27

Formula: F = (SSB/df_between) ÷ (SSW/df_within)

Step-by-step with your numbers:
1. Values used:
2. Group 1 size = 10
3. Group 1 mean = 20
4. Group 1 SD = 3
5. Group 2 size = 10
6. Group 2 mean = 24
7. Group 2 SD = 3.5
8. Group 3 size = 10
9. Group 3 mean = 19
10. Group 3 SD = 2.8
11.
12. F-statistic = 7.219
13. df between = Group 1 mean / Group 1 size = 20 / 10 = 2
14. df within = 27
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One-way ANOVA tests whether several group means differ more than chance would predict.

The math behind it

It compares between-group variance to within-group variance: F = MS_between ÷ MS_within. A large F suggests real differences.

Worked example

Means 20/24/19 → F ≈ 6.4, df 2 and 27.

FAQ

What does a big F mean?

Compare it to the F critical value; if larger, at least one group mean differs significantly.