Monthly Archives: March 2012

Capturing Tick Data via C#, Interactive Brokers, and MySQL

March 3, 2012
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Capturing Tick Data via C#, Interactive Brokers, and MySQL

Interactive Brokers is a discount brokerage that provides a good API for programatically accessing their platform.  The purpose of this post is to create an application that will capture tick level data and save that data into a database for futur...

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Gastwirth’s location estimator

Gastwirth’s location estimator

The problem of outliers – data points that are substantially inconsistent with the majority of the other points in a dataset – arises frequently in the analysis of numerical data.  The practical importance of outliers lies in the fact that even a few of these points can badly distort the results of an otherwise reasonable data analysis.  This outlier-sensitivity...

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R versus Stata Redux

March 3, 2012
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I've used both R and Stata for a long time, but these days I use Stata much more frequently than R. While R is useful for some kinds of graphics (especially three-dimensional graphics) and some statistical procedures (for example, finite mixture models...

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NIT: Fatty acids study in R – Part 002

March 2, 2012
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NIT: Fatty acids study in R – Part 002

> library(chemometrics)> fatmsc_nipals<-nipals(fat_msc,a=10,it=160)> CPs<-seq(1,10,by=1)> matplot(CPs,t(fatmsc_nipals$T),lty=1,pch=21,  + xlab="PC_number",ylab="Explained_Var")In the 2D plot, we can see that with 3 or 4 principal...

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The German DIN33430 – Analysis of acceptance with R

March 2, 2012
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The German DIN33430 – Analysis of acceptance with R

The german DIN33430 defines quality standards that must be met in “job-related proficiency assessments”, the qualifications of the responsible parties involved, as well as the creation, execution and evaluation of such assessments. Licensed persons are published on a website (german). … Weiterlesen →

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New data visualization features in ggplot2 update

March 2, 2012
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New data visualization features in ggplot2 update

Hadley Wickham has just released an update to the ggplot2 graphics package for R. Version 0.9.0 significantly speeds up the process of rendering graphics, and the documentation is much improved (including the addition of many new examples). This update also adds a bunch of new features, which are documented in this 40-page "changes and additions" guide. Here's a sampling...

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What is R-index

March 2, 2012
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What is R-index

R index is developed in interpreting signal detection data for human perception. In sensory research it is used to interpret ranking data. The value one gets out of an R-index calculation is interpreted as a confusion between samples tested. It has bee...

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How to square numbers in your head

March 2, 2012
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How to square numbers in your head

MENTALLY MULTIPLY NUMBERS BY THEMSELVES Assume you know your multiplication tables up to 10x10. Here's how to compute the squares of numbers from 11 to 100.

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When Venn diagrams are not enough – Visualizing overlapping data with Social Network Analysis in R

March 2, 2012
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When Venn diagrams are not enough – Visualizing overlapping data with Social Network Analysis in R

I recently thought about ways to visualize medications and their co-occurences in a group of children. As long as you want to visualize up to  4 different medications you can simply use Venn diagrams. There is a very nice R-package to generate these kind of graphics for you (for a  description see: Chen and Boutros, 2011). But

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A terrible 2000 words

March 2, 2012
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A terrible 2000 words

I've only just started looking at the homicide data made available by the Philadelphia Inquirer in my free time (which is hard to come by lately). I've been thinking about what sorts of statistics I could do, or what kinds of additional data sets I cou...

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