Monthly Archives: September 2009

Adjusting Correlations for Reliability | Attenuation Formula

September 28, 2009
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Adjusting Correlations for Reliability | Attenuation Formula

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...

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Psychology Statistics 101 | R or SPSS

September 28, 2009
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Psychology Statistics 101 | R or SPSS

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...

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How to Import MS Excel Data into R

September 26, 2009
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How to Import MS Excel Data into R

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:

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

September 25, 2009
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Formatting a Table in Word | R to Tab-Delimited to APA Style

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...

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Non-parametric Methods

September 24, 2009
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Non-parametric Methods

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...

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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...

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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...

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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...

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Example 7.13: Read a file with two lines per observation

September 24, 2009
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Example 7.13: Read a file with two lines per observation

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...

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R Function of the Day: cut

September 23, 2009
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This post originally appeared on my Wordpress blog on September 23, 2009. I present it here in its original form. The R Function of the Day series will focus on describing in plain language how certain R functions work, focusing on simple ex...

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