Blog Archives

R Tutorial Series: Centering Variables and Generating Z-Scores with the Scale() Function

March 1, 2012
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R Tutorial Series: Centering Variables and Generating Z-Scores with the Scale() Function

Centering variables and creating z-scores are two common data analysis activities. While they are relatively simple to calculate by hand, R makes these operations extremely easy thanks to the scale() function. Tutorial FilesBefore we begin, you may wan...

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R Tutorial Series: Citing R with EndNote

January 6, 2012
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R Tutorial Series: Citing R with EndNote

Unfortunately, due to the vexing complexities of academic style guides and the limitations of associated software packages, citing a non-standard name, such as Cher, Prince, or R Development Core Team can be problematic. Thankfully, I have discovered a...

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R Tutorial Series: Exploratory Factor Analysis

October 24, 2011
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R Tutorial Series: Exploratory Factor Analysis

Exploratory factor analysis (EFA) is a common technique in the social sciences for explaining the variance between several measured variables as a smaller set of latent variables. EFA is often used to consolidate survey data by revealing the groupings ...

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The R Programming Wikibook

July 8, 2011
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The R Programming Wikibook

The R Programming wikibook is an open source community project that "aims to create a cross-disciplinary practical guide to the R programming language." It was launched in June 2011 and is seeking content and contributors. The full call for the R Progr...

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R Tutorial Series: 2011 ANOVA Article Data

March 28, 2011
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R Tutorial Series: 2011 ANOVA Article Data

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: 2011 ANOVA Article Data

March 28, 2011
By
R Tutorial Series: 2011 ANOVA Article Data

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...

Read more »

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

March 14, 2011
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R Tutorial Series: Applying the Reshape Package to Organize ANOVA Data

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: Applying the Reshape Package to Organize ANOVA Data

March 14, 2011
By
R Tutorial Series: Applying the Reshape Package to Organize ANOVA Data

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...

Read more »

R Tutorial Series: ANOVA Pairwise Comparison Methods

March 7, 2011
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R Tutorial Series: ANOVA Pairwise Comparison Methods

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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R Tutorial Series: ANOVA Pairwise Comparison Methods

March 7, 2011
By
R Tutorial Series: ANOVA Pairwise Comparison Methods

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...

Read more »