300 search results for "ANova"

Formulae in R: ANOVA and other models, mixed and fixed

January 10, 2013
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R’s formula interface is sweet but sometimes confusing. ANOVA is seldom sweet and almost always confusing. And random (a.k.a. mixed) versus fixed effects decisions seem to hurt peoples’ heads too. So, let’s dive into the intersection of these three. I’m aware that there are lots of packages for running ANOVA models that make things nicer

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N-Way ANOVA

September 15, 2012
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N-Way ANOVA example Two-way analysis of variance is where the rubber hits the road, so to speak. This extends the concepts of ANOVA with only one factor to two factors. When there are two factors this means that there can be an interaction between the two factors that should be tested. As one might expect

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One-Way ANOVA

September 11, 2012
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One-Way ANOVA Analysis of variance is a tool used for a variety of purposes. Applications range from a common one-way ANOVA, to experimental blocking, to more complex nested designs. This first ANOVA example provides the necessary tools to analyze data using this technique. This example will show a basic one-way ANOVA. I will save the

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Confidence intervals with tiers: functions for between-subjects (independent measures) ANOVA

June 21, 2012
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Confidence intervals with tiers: functions for between-subjects (independent measures) ANOVA

In a previous post I showed how to plot difference-adjusted CIs for between-subjects (independent measures) ANOVA designs (see here). The rationale behind this kind of graphical display is introduced in Chapter 3 of Serious stats (and summarized in my earlier blog post). In a between-subjects – or in indeed in a within-subjects (repeated measures) – design

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Bayesian ANOVA for sensory panel profiling data

April 30, 2012
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Bayesian ANOVA for sensory panel profiling data

In this post it is examined if it is possible to use Bayesian methods and specifically JAGS to analyze sensory profiling data. The aim is not to obtain different results, but rather to confirm that the results are fairly similar. The data used is the c...

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Graphing between-subject confidence intervals for ANOVA

March 19, 2012
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This is a quick follow up to my earlier post that discussed how to graph CIs for within-subjects (repeated measures) ANOVA designs. My forthcoming book Serious stats describes how to do this for between-subjects designs (a much simpler proble...

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Independent measures (between-subjects) ANOVA and displaying confidence intervals for differences in means

March 18, 2012
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Independent measures (between-subjects) ANOVA and displaying confidence intervals for differences in means

In Chapter 2 (Confidence Intervals) of Serious stats I consider the problem of displaying confidence intervals (CIs) of a set of means (which I illustrate with the simple case of two independent means). Later, in Chapter 16 (Repeated Measures ANOVA), I consider the trickier problem of displaying of two or more means from paired or

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Functional ANOVA using INLA – update

February 29, 2012
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Functional ANOVA using INLA – update

INLA author Håvard Rue wrote me to point out a problem in the Functional ANOVA code given in this post. I made a mistake in setting the precision of the fixed effects (I used “default” instead of “prec”). I’ve put Håvard’s corrected version of the code below.  

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Power and Sample Size for Repeated Measures ANOVA with R

January 20, 2012
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Power and Sample Size for Repeated Measures ANOVA with R

Background One of my colleagues is an academic physical therapist (PT), and he's working on a paper to his colleagues related to power, sample size, and navigating the thicket of trouble that surrounds those two things. We recently got together to walk through some of the issues, and I thought I would share some of the wildlife we observed...

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Functional ANOVA using INLA

January 13, 2012
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Functional ANOVA using INLA

Ramsay and Silverman’s Functional Data Analysis is a tremendously useful book that deserves to be more widely known. It’s full of ideas of neat things one can do when part of a dataset can be viewed as a set of

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