# 383 search results for "anova"

## R Tutorial Series: ANOVA Pairwise Comparison Methods

March 7, 2011
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When we have a statistically significant effect in ANOVA and an independent variable of more than two levels, we typically want to make follow-up comparisons. There are numerous methods for making pairwise comparisons and this tutorial will demonstrate...

## Anova – Type I/II/III SS explained

March 2, 2011
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Not my post, just bookmarking this. It’s from http://goanna.cs.rmit.edu.au/~fscholer/anova.php ANOVA (and R) The ANOVA Controversy ANOVA is a statistical process for analysing the amount of variance that is contributed to a sample by different factors. It was initially derived by R. A. Fisher in 1925, for the case of balanced data (equal numbers of observations

## R Tutorial Series: Two-Way ANOVA with Unequal Sample Sizes

February 28, 2011
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When the sample sizes within the levels of our independent variables are not equal, we have to handle our ANOVA differently than in the typical two-way case. This tutorial will demonstrate how to conduct a two-way ANOVA in R when the sample sizes withi...

## R Tutorial Series: Two-Way Repeated Measures ANOVA

February 21, 2011
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Repeated measures data require a different analysis procedure than our typical two-way ANOVA and subsequently follow a different R process. This tutorial will demonstrate how to conduct two-way repeated measures ANOVA in R using the Anova() function fr...

## R Tutorial Series: One-Way Repeated Measures ANOVA

February 14, 2011
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Repeated measures data require a different analysis procedure than our typical one-way ANOVA and subsequently follow a different R process. This tutorial will demonstrate how to conduct one-way repeated measures ANOVA in R using the Anova(mod, idata, i...

## R Tutorial Series: Two-Way ANOVA with Interactions and Simple Main Effects

February 7, 2011
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When an interaction is present in a two-way ANOVA, we typically choose to ignore the main effects and elect to investigate the simple main effects when making pairwise comparisons. This tutorial will demonstrate how to conduct pairwise comparisons when...

## Post-hoc Pairwise Comparisons of Two-way ANOVA

February 4, 2011
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I read this post today by John Quick. I was a little taken back when he used a pairwise t-test for post hoc analysis. In a contradiction the t-test did not show differences in the treatment means when the ANOVA model did. This is because the pairwise.t.test does not take into account the two-way anova,

## R Tutorial Series: Two-Way ANOVA with Pairwise Comparisons

January 31, 2011
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By extending our one-way ANOVA procedure, we can test the pairwise comparisons between the levels of several independent variables. This tutorial will demonstrate how to conduct pairwise comparisons in a two-way ANOVA. Tutorial FilesBefore we begin, yo...

## R Tutorial Series: One-Way ANOVA with Pairwise Comparisons

January 24, 2011
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When we have more than two groups in a one-way ANOVA, we typically want to statistically assess the differences between each group. Whereas a one-way omnibus ANOVA assesses whether a significant difference exists at all amongst the groups, pairwise com...

## R Tutorial Series: Two-Way Omnibus ANOVA

January 17, 2011
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As with the one-way case, testing the omnibus hypothesis via two-way ANOVA is simple process in R. This tutorial will explore how R can be used to perform a two-way ANOVA to test the difference between two (or more) group means. Tutorial FilesBefore we...