Below, we give the R code to plot the PDF and the CDF for normal distributions. We wish to get charts quite similar to the ones read on Wikipedia (Normal Distribution). The resulting charts are shown at the bottom. Notice that … Continue reading →

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I have tried one of my previous scripts with an updated igraph version and I got an interesting (pretty much unexpected) error:At type_indexededgelist.c:269 : invalid (odd) length of edges vector, Invalid edge vectorThe problem is that it was a well-te...

I might be the 393rd blogger on the R-bloggers.com :-) http://www.r-bloggers.com/Wohoo!

Suppose that you accepted my argument from the last two posts on halo effects and bifactor models. As you might recall, I argued that when respondents complete rating scales, they predominating rely on their generalized impression with a more minor role played by the specific features that the ratings were written to measure. Consequently, we...

More and more makers of electronic devices use standard storage media to record data. Sometimes this is central to the device's function, as in a camera, so that the data must be easy to recover. Other times, it's effectively incidental, and the device maker may not provide easy access to the stored data....

This guest post is by Douglas McNair MD PhD, Engineering Fellow & President, Cerner Math Inc. -- ed. RevoScaleR scaling big-data modeling performance for real-time health data analysis at Cerner The size of data sets is increasing much more rapidly than the speed of cores, of RAM, and of disk drives. This is particularly true of electronic health records...

Using progress bars in R scripts can provide valuable timing feedback during development and additional polish to final products. winProgressBar and setWinProgressBar are the primary functions for creating progress bars in R. Progress bars, and progress indicators in general, are relatively uncommon in R programming. This makes sense, as they can add bloat and, being The post Progress...

About 8 years ago, I was sitting in class listening to a guest lecturer talk about how community events can be described like celestial bodies with their own gravity, where the size and importance of the event would attract more people, from farther away. Much like a black hole, where the bigger the mass of the black hole the...

The paper is “Not Fooled by Randomness: Using Random Portfolios to Analyze Investment Funds” by Roberto Stein. Here is an explanation of the idea of random portfolios. Favorite sentence The real question here is whether we’re actually measuring skill, or these are still measures of performance, so influenced by extraneous factors that the existence of … Continue reading...