What is likely to happen if you do multiple pairwise comparisons?

What is likely to happen if you do multiple pairwise comparisons?

When we make multiple comparisons using the p=. 05 criterion, we have a chance of making a Type I error on each comparison. Also, the more comparisons we make, the more likely we are to make at least one Type I error. The chance of committing at least one Type I error for a set of comparisons can be estimated as c * .

How do you interpret contradictory results between ANOVA and multiple pairwise comparisons?

Interpretation of contradictory results between ANOVA and multiple pairwise comparisons

1. The p-value computed by the ANOVA is lower than the alpha significance level (e.g. 0,05).
2. All the p-values computed by the multiple pairwise comparisons test are higher than the alpha significance level.

What does a pairwise comparison show?

Pairwise comparisons are methods for analyzing multiple population means in pairs to determine whether they are significantly different from one another. As an example, many different statistical methods have been developed for determining if there exists a difference between population means.

Is Bonferroni too conservative?

The Bonferroni procedure ignores dependencies among the data and is therefore much too conservative if the number of tests is large.

What is the purpose of doing a multiple comparison?

The purpose of most multiple-comparisons procedures is to control the “overall significance level” for some set of inferences performed as a follow-up to ANOVA.

How do you know if pairwise comparisons are significant?

If the adjusted p-value is less than alpha, reject the null hypothesis and conclude that the difference between a pair of group means is statistically significant. The adjusted p-value also represents the smallest family error rate at which a particular null hypothesis is rejected.

How do you know if ANOVA is statistically significant?

The most common threshold is p < 0.05, which means that the data is likely to occur less than 5% of the time under the null hypothesis. When the p-value falls below the chosen alpha value, then we say the result of the test is statistically significant.

How do you analyze pairwise comparisons?

Pairwise Comparison Steps:

1. Compute a mean difference for each pair of variables.
2. Find the critical mean difference.
3. Compare each calculated mean difference to the critical mean.
4. Decide whether to retain or reject the null hypothesis for that pair of means.

What does pairwise mean statistics?

Pairwise means to form all possible pairs — two items at a time — from a set. For example, in the set {1,2,3} all possible pairs are (1,2),(2,3),(1,3).

What is the purpose of using a multiple comparisons test after an ANOVA?

Multiple comparison analysis tests are extremely important because while the ANOVA provides much information, it does not provide detailed information about differences between specific study groups, nor can it provide information on complex comparisons.

What is benjamini Hochberg?

The Benjamini-Hochberg Procedure is a powerful tool that decreases the false discovery rate. Adjusting the rate helps to control for the fact that sometimes small p-values (less than 5%) happen by chance, which could lead you to incorrectly reject the true null hypotheses.