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...

Using doc-view with auto-revert to view LaTeX PDF output in Emacs

October 3, 2009
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$Using doc-view with auto-revert to view LaTeX PDF output in Emacs$

When I am authoring a document in Emacs, such as a report or my CV, it is useful for me to compile the source file periodically to see what the resulting file PDF looks like. I used to run a separate PDF viewer to look at the output, but I now have a complete Emacs

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...

smoothScatter in base R

October 2, 2009
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smoothScatter function is now available also in base R - in the recommended package graphics that is shipped with R. Originally this function was in the genepplotter package from Bioconductor. I really like it since it can nicely plot large datasets. B...

smoothScatter in base R

October 2, 2009
By

smoothScatter function is now available also in base R - in the recommended package graphics that is shipped with R. Originally this function was in the genepplotter package from Bioconductor. I really like it since it can nicely plot large datasets. B...

Make Safari behave as Firefox

Some weeks ago I switched from Firefox to Safari. While Safari is -- in my experience -- quicker, better looking, and has Top Sites, I was also missing some functionality of firefox. To be more precise, I missed the 'search when start typing' option, a...

R Object Tooltips in ESS

October 1, 2009
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This post originally appeared on my Wordpress blog on October 1, 2009. I present it here in its original form. Whether at work or for personal projects, I use ESS a lot to perform interactive data analyses. The ability to write, edit, and su...

R Object Tooltips in ESS

October 1, 2009
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This post originally appeared on my Wordpress blog on October 1, 2009. I present it here in its original form. Whether at work or for personal projects, I use ESS a lot to perform interactive data analyses. The ability to write, edit, and su...

R Object Tooltips in ESS

October 1, 2009
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Whether at work or for personal projects, I use ESS a lot to perform interactive data analyses. The ability to write, edit, and submit R commands to an interactive R process is simply something I cannot imagine analyzing data without. An example One thing that I end up having to do a lot is inspect

R: The Dummies Package

September 30, 2009
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R-2.9.2 was released in August. While R can be considered stable and battle-ready, it is also far from stagnation. It is humbling to see such an intelligent and vibrant community helping CRAN grow faster than ever. Every day I see a new package or read a new comment on R-Help

Measuring performance of functions in R

In R you can use the system.time(function) function to test the time it takes to execute a function. Because I had to do some extended performance testing in R, I wrote a new function based on system.time which gives you the possibility to run multiple...

Example 7.14: A simple graphic of sales

September 29, 2009
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In this example, we show a simple plot of the sales rank data read in as shown in example 7.13.SASIn SAS, we use the symbol statement (section 5.3) to request small (with the h option) dots (with the v option, and that the dots not be connected (with the i option. (See sections 5.2.2, 5.3.9 for more details.)we...

RInside release 0.1.1, and a fresh example

September 29, 2009
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Last week's 0.1.0 release of RInside, and the first to have been published on CRAN, still had some issues with builds and use on OS X. Thanks to testing and fixes by Jan de Leeuw, Jeff Horner and particularly Simon Urbanked, things are said to be better now with the new release 0.1.1 which went onto CRAN yesterday. So no new features,...

RInside release 0.1.1, and a fresh example

September 29, 2009
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Last week's 0.1.0 release of RInside, and the first to have been published on CRAN, still had some issues with builds and use on OS X. Thanks to testing and fixes by Jan de Leeuw, Jeff Horner and particularly Simon Urbanked, things are said to be bette...

RInside release 0.1.1, and a fresh example

September 29, 2009
By

Last week's 0.1.0 release of RInside, and the first to have been published on CRAN, still had some issues with builds and use on OS X. Thanks to testing and fixes by Jan de Leeuw, Jeff Horner and particularly Simon Urbanked, things are said to be better now with the new release 0.1.1 which went onto CRAN yesterday. So no new features,...

WordPress Blogging with R in 3 Steps

September 29, 2009
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A few people have emailed me and enquired about the use of tools mentioned at the end of this post to make blogposts with embedded R-commands. Below is a small step-by-step walkthrough of how to accomplish this. Write your blog post in a simple text file, you can include formatting using asciidoc syntax. Let’s

WordPress Blogging with R in 3 Steps

September 29, 2009
By

A few people have emailed me and enquired about the use of tools mentioned at the end of this post to make blogposts with embedded R-commands. Below is a small step-by-step walkthrough of how to accomplish this. Write your blog post in a simple tex...

Survive R

September 29, 2009
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New PDF slides version (presented at the Bay Area R Users Meetup October 13, 2009). We at Win-Vector LLC appear to like R a bit more than some of our, perhaps wiser, colleagues ( see: Choose your weapon: Matlab, R or something else? and R and data ). While we do like R (see: Exciting Related posts:

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...

How to Import MS Excel Data into R

September 26, 2009
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s Sir Francis Bacon said, “Histories make men wise; poets witty; the mathematics subtile; natural philosophy deep; moral grave; logic and rhetoric able to contend.” And Windows stupid. He should have added the last sentence if he were a Windows user in this age. 1. Avoid Using M\$ Excel A lot of R users often ask this question:

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...

Non-parametric Methods

September 24, 2009
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A statistical method is called non-parametric if it makes no assumption on the population distribution or sample size. This is in contrast with most parametric methods in elementary statistics that assume the data is quantitative, the population...

digest 0.4.0 and 0.4.1

September 24, 2009
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After almost two years, I just made a small update to the digest package for R by adding sha-256 as another supported hashing function. While at this, a few minor edits where made here or there. Version 0.4.0 also included a file src/Makefile.win b...

digest 0.4.0 and 0.4.1

September 24, 2009
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After almost two years, I just made a small update to the digest package for R by adding sha-256 as another supported hashing function. While at this, a few minor edits where made here or there. Version 0.4.0 also included a file src/Makefile.win but a...

digest 0.4.0 and 0.4.1

September 24, 2009
By

After almost two years, I just made a small update to the digest package for R by adding sha-256 as another supported hashing function. While at this, a few minor edits where made here or there. Version 0.4.0 also included a file src/Makefile.win b...

Example 7.13: Read a file with two lines per observation

September 24, 2009
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In example 7.6 we showed how to retrieve the Amazon sales rank of a book. A cron job on one of our machines grabs the sales rank hourly. We’d like to use this data to satisfy our curiosity about when and how often a book sells. A complication is that the result of the cron job is a...