Monthly Archives: June 2013

Mean and Median

June 8, 2013
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Mean in R is computed using the function mean. Consider the scores of 20 MSU-IIT students in Stat 101 exam with a hundred items: 70, 78, 66, 65, 50, 53, 48, 88, 95, 80, 85, 84, 81, 63, 68, 73, 75, 84, 49, and 77. Compute and interpret the mean and medi...

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Using Metadata to find Paul Revere

June 8, 2013
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Using Metadata to find Paul Revere

London, 1772. I have been asked by my superiors to give a brief demonstration of the surprising effectiveness of even the simplest techniques of the new-fangled Social Networke Analysis in the pursuit of those who would seek to undermine the liberty enjoyed by His Majesty’s subjects. This is in connection with the discussion of the role of “metadata” in

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Bulk search for domain names using R

June 8, 2013
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# There are several domain name servers that allow # for bulk searching of domain names.# http://www.godaddy.com/bulk-domain-search.aspx# http://www.namestation.com/bulk-domain-search# However, they do not provide any wildcard support # and instead exp...

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Matrix Operations

June 8, 2013
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Matrix manipulation in R are very useful in Linear Algebra. Below are lists of common yet important functions in dealing operations with matrices:Transpose - tMultiplication - %*%Determinant - detInverse - solve, or ginv of MASS libraryEigenvalues and ...

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R and MongoDB

June 7, 2013
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R and MongoDB

MongoDB is a document-based noSQL database. Different from the relational database storing data in tables with rigid schemas, MongoDB stores data in documents with dynamic schemas. In the demonstration below, I am going to show how to extract data from a MongoDB with R. Before starting the R session, we need to install the MongoDB

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Hey, I Just did a Significance Test!

June 7, 2013
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Hey, I Just did a Significance Test!

I’ve seen it happens quite often. The sig test. Somebody simply needs to know the p-value and that one number will provide all of the information about the study that they need to know. The dataset is presented and the client/boss/colleague/etc invariably asks the question “is it significant?” and “what’s the correlation?”. To quote R.A.

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Robust logistic regression

June 7, 2013
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Corey Yanofsky writes: In your work, you’ve robustificated logistic regression by having the logit function saturate at, e.g., 0.01 and 0.99, instead of 0 and 1. Do you have any thoughts on a sensible setting for the saturation values? My intuition suggests that it has something to do with proportion of outliers expected in the The post Robust...

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Crayfish or crawdad? Mapping US dialect variations with R

June 7, 2013
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Crayfish or crawdad? Mapping US dialect variations with R

I grew up in Australia, where I learned to speak English. Or so I thought: when I moved overseas to the UK, and especially when I moved to the States, I soon learned these are distinct cultures separated by a common language. Words which I previously had no context for being different anywhere else, such as "runners" ("sneakers"), "lemonade"...

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The Rcpp Book is now shipping

My book about Rcpp (and its R and C++ integration) is now available from Springer. Amazon still lists it as not-yet-released; I expect this to change in the next few days.

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Happy Birthday rasterVis!

Happy Birthday rasterVis!

Two years ago the first version of rasterVis was submitted to R-Forge and some weeks after the first stable version was …Continuar leyendo »

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