Blog Archives

Factor Analysis in R

October 7, 2009
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This post shows an example of running a basic factor analysis in R.Additional Resources:Quick-Rpsych packageJame's Steiger's exampleFactoMineR packageThe Example:The example is based on responses by 117 university students to a 50 item version of the I...

Efficient Variable Selection in R

October 7, 2009
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This post sets out my procedure for efficiently and reliably selecting variables from a data.frame in RTHE PROBLEMFor years I have been tormented by the hassle of selecting variables in a data.frame. I often work with psychological datasets with hundre...

Including R Code in a Blog Post

October 5, 2009
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This post discusses ways of including formatted code in a blog post.I often write posts that include computer code. This might be R code, SPSS syntax, an Inquisit script, or a Visual Basic Macro.The Problem:Initially I did not know how to include this ...

Calculating Scale Scores for Psychological Tests

October 4, 2009
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This post discusses how to calculate scale scores for multi-item scales. A lot of psychological research uses multi-item scales (e.g., personality tests, symptoms check lists, surveys, etc.). This post focuses on the issues involved with computing thes...

Data Mining and Statistics Video Course

October 3, 2009
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David Mease has an online course presented with complete videos (Statistics 202: Statistical Aspects of Data Mining ). The course uses Excel and R.I might update this post with a few notes below on what is covered as I get a chance to watch t...

Blogs on R | Statistics

September 28, 2009
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What are the current blogs on R? What do they cover?What makes a good blog on R?Of course different readers look for different things, but for me a good blog on R:Provides a Gateway: The blog discovers and shares useful external material and expla...

Adjusting Correlations for Reliability | Attenuation Formula

September 28, 2009
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This post discusses ways of adjusting correlations for reliability.Classical Test Theory states that an Observed variable is True Score plus Error. The true score variable is latent. In psychology theoretical interest typically relates more to the late...

Psychology Statistics 101 | R or SPSS

September 28, 2009
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Dan Wright has placed his Quantitative Methods 1 course online. The course offers instructions both in R and SPSS (PASW).It is an interesting case study in  how to integrate R into a psychology quantitative methods course at the undergraduate leve...

Formatting a Table in Word | R to Tab-Delimited to APA Style

September 25, 2009
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The following post sets out my procedure for importing a tab-delimited table of data produced in R  into Microsoft Word and formatting it.Prior to importing table:Run macro which does the followingInsert Caption: References - Insert Capt...

Linking text, results, and analyses: Increasing transparency and efficiency

September 20, 2009
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I have recently been thinking about the relationship between text in a final report and data analysis. The broader concern is with making the conduct and reporting of statistical analyses more transparent. I am inspired by the ideas of literate program...