Is a pairwise comparison a post hoc test?
Post-hoc pairwise comparisons are commonly performed after significant effects have been found when there are three or more levels of a factor. We will demonstrate the how to conduct pairwise comparisons in R and the different options for adjusting the p-values of these comparisons given the number of tests conducted.
What is a repeated measures design test used for?
Repeated measures design can be used to conduct an experiment when few participants are available, conduct an experiment more efficiently, or to study changes in participants’ behavior over time.
How do you compare two groups?
A common way to approach that question is by performing a statistical analysis. The two most widely used statistical techniques for comparing two groups, where the measurements of the groups are normally distributed, are the Independent Group t-test and the Paired t-test.
Is repeated measures the same as paired t-test?
A repeated-measures t-test (also known by other names such as the ‘paired samples’ or ‘related’ t-test) is what you should use in situations when your design is within participants. In a within participants design, participants contribute data for the dependent variable in ALL of the experimental conditions.
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.
What is a pairwise comparison in ANOVA?
Description. The typical application of pairwise comparisons occurs when a researcher is examining more than two group means (i.e., the independent variable has more than two levels), and there is a statistically significant effect for the omnibus ANOVA.
When to use repeated measures in a study?
A repeated-measures ANOVA design is sometimes used to analyze data from a longitudinal study, where the requirement is to assess the effect of the passage of time on a particular variable.
Which is the best procedure for multiple comparisons?
Virtually all the multiple comparison procedures can be computed using the lowly ttest; either a ttest for independent means, or a ttest for related means, whichever is appropriate. Certainly textbooks give different procedures for different tests, but the basic underlying structure is the ttest.
Is the repeated measures ANOVA the same as the one way ANOVA?
This is the equivalent of a one-way ANOVA but for repeated samples and is an extension of a paired-samples t-test. Repeated measures ANOVA is also known as ‘within-subjects’ ANOVA.
Can a ttest be used for multiple comparisons?
Forget about all the neat formulae that you find in a text on statistical methods, mine included. Virtually all the multiple comparison procedures can be computed using the lowly ttest; either a ttest for independent means, or a ttest for related means, whichever is appropriate.