# 319 search results for "ANOVA"

## One-way ANOVAs in R – including post-hocs/t-tests and graphs

May 11, 2011
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In this post, I go over the basics of running an ANOVA using R. The dataset I’ll be examining comes from this website, and I’ve discussed it previously (starting here and then here). I’ve not seen many examples where someone runs through the … Continue reading →

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## Adonis (PERMANOVA) – Assumptions

April 26, 2011
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Before you use PERMANOVA (R-vegan function adonis) you should read the user notes for the original program by the author (Marti J. Anderson) who first came up with this method. An important assumtption for PERMANOVA is same "multivariate spread&qu...

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## R Tutorial Series: 2011 ANOVA Article Data

March 28, 2011
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Having wrapped up a recent flurry of R ANOVA articles (and exhausted my knowledge of the subject), I decided to take a look at the R Tutorial Series' Google Analytics data from the past few months. Since I posted the Two-Way Omnibus ANOVA article on J...

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## R Tutorial Series: Applying the Reshape Package to Organize ANOVA Data

March 14, 2011
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As demonstrated in the preceding ANOVA tutorials, data organization is central to conducting ANOVA in R. In standard ANOVA, we used the tapply() function to generate a table for a single summary function. In repeated measures ANOVA, we used separate da...

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## 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...

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## 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

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## 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...

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## 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...

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## 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...

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## 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...

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