2766 search results for "gis"

Making matrices with zeros and ones

August 30, 2012
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So I was trying to figure out a fast way to make matrices with randomly allocated 0 or 1 in each cell of the matrix. I reached out on Twitter, and got many responses (thanks tweeps!). Here is the solution I came up with. See if you can tell why it...

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Another Great Google Summer of Code 2012 R Project

August 30, 2012
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Another Great Google Summer of Code 2012 R Project

Tradeblotter announced the very nice features that will be added to the PerformanceAnalytics package as a result of the Google Summer of Code (GSOC) 2012 project: “…Matthieu commenced to produce dozens of new functions, extend several more existin...

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F1 2012 Mid-Season Review

August 30, 2012
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F1 2012 Mid-Season Review

Rather belatedly, I got around to posting a series of posts summarising the Formula One season to date: F1 2012 Mid-Season Review – Grid/Classification Analysis: for example, how do the drivers’ grid and final classifications compare? F1 2012 Mid-Season Review – Pit Stops: for example, how does pit stop performance across the teams compare? F1

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Plotting model fits

August 29, 2012
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Plotting model fits

We all know that it is important to plot your data and explore the data visually to make sure you understand it. The same is true for your model fits. First, you want to make sure that the model is fitting...

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Setting Up the Development Version of R

August 28, 2012
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My coworkers at Fred Hutchinson regularly use the development version of R (i.e., R-devel) and have urged me to do the same. This post details how I have set up the development version of R on our Linux server, which I use remotely because it is much faster than my Mac. First, I downloaded the R-devel source into ~/local/, which...

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Newton-Raphson can compute an average

August 28, 2012
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Newton-Raphson can compute an average

In our article How robust is logistic regression? we pointed out some basic yet deep limitations of the traditional full-step Newton-Raphson or Iteratively Reweighted Least Squares methods of solving logistic regression problems (such as in R‘s standard glm() implementation). In fact in the comments we exhibit a well posed data fitting problem that can not Related posts:

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More on Exploring Correlations in R

August 28, 2012
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More on Exploring Correlations in R

About a year ago I wrote a post about producing scatterplot matrices in R. These are handy for quickly getting a sense of the correlations that exist in your data. Recently someone asked me to pull out some relevant statistics (correlation coefficient ...

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Horizon on ggplot2

August 27, 2012
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Horizon on ggplot2

SocialDataBlog’s kind reference in post Horizon plots with ggplot (not) motivated me to finish what the post started.  I knew that ggplot2 would be a little more difficult to use for the purpose of a horizon plot, but I felt compelled to provide...

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Structural Equation Modeling: Separating the General from the Specific (Part II)

August 26, 2012
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Structural Equation Modeling: Separating the General from the Specific (Part II)

As promised in Halo Effects and Multicollinearity (my last post), I will show how to run a confirmatory factor analysis in R to test our bifactor model.  In addition, I will include a dependent variable and fit a structural equation mode...

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A Chlorpleth Map of Free and Reduced Price Lunch in R

August 26, 2012
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A Chlorpleth Map of Free and Reduced Price Lunch in R

Charles Blow has an excellent op-ed in the New York Times about public education this week. The most important point he makes is that the defunding of public education is coming at precisely the time when American school children are most vulnerable:No...

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