184 search results for "Anova"

Functional regression, INLA, and how to build the World’s Slowest Fourier Transform

March 29, 2012
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Functional regression, INLA, and how to build the World’s Slowest Fourier Transform

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R functions for serious stats

March 25, 2012
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R functions for serious stats

UPDATE: Some problems arose with my previous host so I have now updated the links here and elsewhere on the blog. The companion web site for Serious Stats has a zip file with R scripts for each chapter. This contains examples of R code and and all my functions from the book (and a few extras).

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Example 9.24: Changing the parameterization for categorical predictors

March 22, 2012
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Example 9.24: Changing the parameterization for categorical predictors

In our book, we discuss the important question of how to assign different parameterizations to categorical variables when fitting models (section 3.1.3). We show code in R for use in the lm() function, as follows:lm(y ~ x, contrasts=list(x,"contr.trea...

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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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R for Quants, Part II (A)

February 16, 2012
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R for Quants, Part II (A)

This is the second part in a three part series on teaching R to MFE students at CUNY Baruch. The …

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Beware the Friedman test!

February 14, 2012
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Beware the Friedman test!

In section 10.4.4 of Serious stats (Baguley, 2012) I discuss the rank transformation and suggest that it often makes sense to rank transform data prior to application of conventional ‘parametric’ least squares procedures such as t tests or one-way ANOVA. There are several advantages to this approach over the usual approach (which involves learning and applying a new test such as Mann-Whitney U,

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Confirming SSR, SSE, and SST using matrix in R

February 1, 2012
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Confirming SSR, SSE, and SST using matrix in R

The codes below was done in our regression laboratory class. Here, we run first the data in SPSS, and take the ANOVA output where we can find the computed values of SSR, SSE, and SST.ANOVAb Model Sum of Squares df Mean Square F Sig. 1 Regress...

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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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