311 search results for "anova"

Two-Way ANOVA with Repeated Measures

August 18, 2015
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Two-Way ANOVA with Repeated Measures

NOTE: This post only contains information on repeated measures ANOVAs, and not how to conduct a comparable analysis using a linear mixed model. For that, be on the lookout for an upcoming post! When I was studying psychology as an undergraduate, one of my biggest frustrations with R was the lack of quality support for

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ANOVAs and Geomorph

April 1, 2015
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Within geomorph are several functions that perform analysis of variance (ANOVA), includingprocD.lm()procD.pgls()advanced.procD.lm()pairwiseD.test()pairwise.slope.test()trajectory,analysis()bilat.symmetry()plotAllometry() Inherent in all of these functions is a common philosophy for ANOVA (although other philosophies exist).  The geomorph ANOVA philosophy is that: (1) resampling (randomization) procedures are used to generate empirical sampling distributions to assess significance of effects, (2) effect sizes are estimated as standard deviates from such...

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A function to help graphical model checks of lm and ANOVA

March 25, 2015
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A function to help graphical model checks of lm and ANOVA

As always a more colourful version of this post is available on rpubs. Even if LM are very simple models at the basis of many more complex ones, LM still have some assumptions that if not met would render any interpretation from the models plainly wrong. In my field of research most people were taught

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Generating ANOVA-like table from GLMM using parametric bootstrap

February 26, 2015
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Generating ANOVA-like table from GLMM using parametric bootstrap

This article may also be found on RPubs: http://rpubs.com/hughes/63269 In the list of worst to best way to test for effect in GLMM the list on http://glmm.wikidot.com/faq state that parametric bootstrapping is among the best options. PBmodcomp in the pbkrtest package implement such parametric bootstrapping by comparing a full model to a null one. The

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Performing ANOVA Test in R: Results and Interpretation

June 23, 2014
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Performing ANOVA Test in R: Results and Interpretation

When testing an hypothesis with a categorical explanatory variable and a quantitative response variable, the tool normally used in statistics is Analysis of Variances, also called ANOVA.In this post I am performing an ANOVA test using the R programming language, to a...

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ANOVA and Tukey’s test on R

June 13, 2013
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ANOVA and Tukey’s test on R

OBS: This is a full translation of a portuguese version. In many different types of experiments, with one or more treatments, one of the most widely used statistical methods is analysis of variance or simply ANOVA . The simplest ANOVA can be called “one way” or “single-classification” and involves the analysis of data sampled from The post ANOVA...

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Serious stats: using multilevel models to get accurate inferences for repeated measures ANOVA

June 13, 2013
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This article from my other blog may be of interest to readers of this blog: http://seriousstats.wordpress.com/2013/04/18/using-multilevel-models-to-get-accurate-inferences-for-repeated-measures-anova-designs/

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Analytical and simulation-based power analyses for mixed-design ANOVAs

May 21, 2013
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Analytical and simulation-based power analyses for mixed-design ANOVAs

In this post I show some R-examples on how to perform power analyses for mixed-design ANOVAs. The first example is analytical—and adapted from formulas used in G*Power (Faul et al., 2007), and the second example is a Monte Carlo simulation. Read more

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Simulation shows gain of clmm over ANOVA is small

May 5, 2013
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Simulation shows gain of clmm over ANOVA is small

After last post's setting up for a simulation, it is now time to look how the models compare. To my disappointment with my simple simulations of assessors behavior the gain is minimal. Unfortunately, the simulation took much more time than I ...

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Using multilevel models to get accurate inferences for repeated measures ANOVA designs

April 18, 2013
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Using multilevel models to get accurate inferences for repeated measures ANOVA designs

It is now increasingly common for experimental psychologists (among others) to use multilevel models (also known as linear mixed models) to analyze data that used to be shoe-horned into a repeated measures ANOVA design. Chapter 18 of Serious Stats introduces multilevel models by considering them as an extension of repeated measures ANOVA models that can

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