P Value Calculator From F Ratio (ANOVA)

Further Information

• ANOVA
• P-Value

What does a one-way ANOVA tell you?

A one-way ANOVA examines the effect of one categorical independent variable (factor) on a continuous dependent variable. The factor divides cases into three or more groups. ANOVA tests for significant differences in the dependent variable's means across these groups.

What are “Groups” or “Levels”?

In ANOVA, "groups" or "levels" refer to distinct categories of the independent variable. For example, in a study on teaching methods, groups might be "lecture," "online," and "hands-on." Each participant belongs to only one group, allowing comparison of the dependent variable across these categories.

What is the difference between one-way ANOVA and t test?

One-way ANOVA compares means across three or more groups, while a t-test compares means between two groups. ANOVA is more versatile for multiple group comparisons, reducing the risk of Type I errors that could occur from multiple t-tests. Both tests assume normal distribution and equal variances.

Do you have to do post hoc test after ANOVA?

Post-hoc tests are not always necessary after ANOVA. They're typically performed when the ANOVA result is significant and you want to determine which specific group differences contribute to this result. If ANOVA is not significant, post-hoc tests are usually unnecessary.

Which post hoc test to use for one-way ANOVA?

If a one-way ANOVA is significant, you can determine which group has the most effect on the dependent variable through post-hoc tests. Common methods include:

1. Tukey’s HSD: Use when you want to compare all possible pairs of group means with good balance between Type I error control and statistical power.
2. Bonferroni: Choose this when you need a simple, conservative approach that strongly controls the family-wise error rate, especially useful for a small number of planned comparisons.
3. Scheffe’s: Opt for this method when you need flexibility to test all possible contrasts among group means, not just pairwise comparisons.
4. Dunnett’s: Select this test when you specifically want to compare multiple treatment groups to a single control group.
5. Games-Howell: Employ this test when your groups have unequal variances or unequal sample sizes, as it doesn’t assume homogeneity of variances.

How to report a post hoc test APA Style

 Post hoc analyses using the Scheffé post hoc criterion for significance indicated that the average number of errors was significantly lower in the white noise condition (M = 12.4, SD = 2.26) than in the other two noise conditions (traffic and industrial) combined (M = 13.62, SD = 5.56), F(3, 27) = 7.77, p = .042.