4904 search results for "git"

Post 1: A Bayesian 2PL IRT model

October 4, 2013
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Post 1: A Bayesian 2PL IRT model

In this post, we define the Two-Parameter Logistic (2PL) IRT model, derive the complete conditionals that will form the basis of the sampler, and discuss our choice of prior specification. We can find the appropriate values of numerically in R … Continue reading →

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First day of State of Food Insecurity (SOFI) 2013

October 2, 2013
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First day of State of Food Insecurity (SOFI) 2013

The FAO flagship publication SOFI 2013 was release yesterday on the 1st of October, the publication is the most important report in monitoring the progress towards the 2015 Millenium Development Goal and ultimately eliminate hunger. I was interest in how the people responded, so I scrapped some data from Twitter and previous work to carry...

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What’s the Most “Concave” State in the U.S.? Using R to Solve a Geography Puzzle

October 1, 2013
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What’s the Most “Concave” State in the U.S.? Using R to Solve a Geography Puzzle

This is a guest post by Todd Schneider and the original link is http://news.rapgenius.com/Atodd-whats-the-most-concave-state-in-the-us-using-r-to-solve-a-geography-puzzle-lyrics. The puzzle: find two points inside the United States such that Both points are in the same state The straight line segment (shortest great circle) connecting them crosses the largest number of distinct states This came up during a recent road trip through Pennsylvania, Maryland, West Virginia,...

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Creating a matrix from a long data.frame

October 1, 2013
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There can never be too many examples for transforming data with R. So, here is another example of reshaping a data.frame into a matrix.Here I have a data frame that shows incremental claim payments over time for different loss occurrence (origin) years...

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Which is the best "Flyover" state?

September 30, 2013
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Which is the best "Flyover" state?

If you were to hop into your personal aircraft, and plotted a straight line course taking off in one state and landing in the SAME state, how many other states might you fly over? On other words, what's the best state for "flyovers" of other states? Todd Schnieder from the Rapgenius engineering team answered that question using the R...

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How heavy is the Siberut macaque? A Bayesian phylogenetic approach

September 30, 2013
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How heavy is the Siberut macaque? A Bayesian phylogenetic approach

Among-species comparisons can include phylogenetic information to account for non-independence arising from shared evolutionary history. Often, phylogenetic topologies and branch lengths are not known exactly, but are estimated with uncertainty. This uncertainty can be accounted for using methods recently described in a neat paper called Bayesian models for comparative analysis integrating phylogenetic uncertainty by Villemereuil et...

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New version of lme4

September 30, 2013
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If you haven't realized it yet, a new version of lme4 (version 1.0-4) was released recently (Sept. 21). For an end-user like me, there were not many changes, but there were a few:No more using the @ operator. After a very helpful email exchange with Be...

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Testing R Packages

September 29, 2013
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This guy th3james claimed Testing Code Is Simple, and I agree. In the R world, this is not anything new. As far as I can see, there are three schools of R users with different testing techniques: tests are put under package/tests/, and a foo-test.Rout.save from R CMD BATCH foo-test.R; testing is done by comparing foo-test.Rout from R CMD check with your foo-test.Rout.save; R...

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Classification with O-PLS-DA

September 29, 2013
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Classification with O-PLS-DA

Partial least squares (PLS) is a versatile algorithm which can be used to predict either continuous or discrete/categorical variables. Classification with PLS is termed PLS-DA, where the DA stands for discriminant analysis.  The PLS-DA algorithm has many favorable properties for dealing with multivariate data; one of the most important of which is how variable collinearity is

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Visualizing “ObamaCare-related” Job Cuts

September 28, 2013
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Visualizing “ObamaCare-related” Job Cuts

I was reviewing RSS feeds when I came across this story about “ObamaCare Employer Mandate: A List Of Cuts To Work Hours, Jobs” over on Investors.com. Efficacy of the law notwithstanding, I thought it might be interesting to visualize the data since the folks over at Investors.com provided a handy spreadsheet that they seem to

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