172 search results for "PCA"

Testing Out my Pitch F/X Data

May 25, 2010
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Testing Out my Pitch F/X Data

I recently got all the Pitch F/X data downloaded from Gameday, and have been fiddling around. I certainly don't have the physics knowledge to really talk about the movement at this point, and I'm still acquainting myself with the data format and what e...

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Tutorial: Principal Components Analysis (PCA) in R

May 20, 2010
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Found this tutorial by Emily Mankin on how to do principal components analysis (PCA) using R. Has a nice example with R code and several good references. The example starts by doing the PCA manually, then uses R's built in prcomp() function to do the s...

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Computational Statistics

May 9, 2010
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Computational Statistics

Do not resort to Monte Carlo methods unnecessarily. When I received this 2009 Springer-Verlag book, Computational Statistics, by James Gentle a while ago, I briefly took a look at the table of contents and decided to have a better look later… Now that I have gone through the whole book, I can write a short

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Fun with R: Clustering and MDS

May 5, 2010
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Fun with R: Clustering and MDS

I've seen K-means clustering, PCA, etc. done some over at Beyond the Boxscore and Baseball Analysts (and the now defunct Statspeak), but I thought I'd just check out some clustering on the young fantasy season using the traditional 5x5 categories with ...

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Compcache on Ubuntu on Amazon EC2

May 4, 2010
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Compcache on Ubuntu on Amazon EC2

The following fully-automatic Bash script downloads, compiles, and initializes compcache version 0.6.2 on Ubuntu Karmic Koala (9.10). This script creates two swaps with a maximum of 4GB uncompressed size each. Two swaps are used to take advantage of 2 CPUs (or CPU cores in a multicore CPU). Compcache is a fascinating memory compression system. The

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Tipping heuristics

April 28, 2010
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Tipping heuristics

INCREDIBLY SIMPLE CALCULATIONS MADE SIMPLE Yes, we all know how to calculate 15% or 20% exactly, but it’s fun to use tipping heuristics and even more fun to make crowded graphs of how they compare to each other. (Sorry for the junky chart. Open for suggestions, in the words of Tom Waits.) Here are a

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Estimating Missing Data with aregImpute() {R}

April 19, 2010
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Missing Data
Soil scientists routinely sample, characterize, and summarize patterns in soil properties in space, with depth, and through time. Invariably, some samples will be lost or sufficient funds required for complete characterization can run out. In these cases the scientist is left with a data table that contains holes (so to speak) in the rows/columns that are...

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alphahull: an R Package for Alpha-Convex Hull

April 16, 2010
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alphahull: an R Package for Alpha-Convex Hull

new paper on the α-convex hull appeared in the Journal of Statistical Software today (http://www.jstatsoft.org/v34/i05/paper). The α-convex hull is an interesting problem which caught my attention long time ago but I didn’t know a solution then. R has a function chull() which can generate (indices of) the convex hull for a series of points. Now

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REvolution R Community 3.2 now available

April 9, 2010
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REvolution R Community, REvolution's free distribution based on R from the R Project, has been updated to version 3.2 and is now available for download for Windows and MacOS. Some features of this release include: Upgraded R engine. This release is based on R 2.10.1, the latest release (as of this writing). This brings many new features to the...

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Demonstrating the Power of F Test with gWidgets

April 2, 2010
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e know the real distribution of the F statistic in linear models — it is a non-central F distribution. Under H0, we have a central F distribution. Given 1 – α, we can compute the probability of (correctly) rejecting H0. I created a simple demo to illustrate how the power changes as other parameters vary,

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