261 search results for "PCA"

Web Scraping Yahoo Search Page via XPath

November 10, 2011
By
Web Scraping Yahoo Search Page via XPath

Seeing as I’m on a bit of an XPath kick as of late, I figured I’d continue on scraping search results but this time from Yahoo.com Rolling my own version of xpathSApply to handle NULL elements seems to have done the trick and so far it’s been relatively easy to do the scraping. I’ve created

Read more »

A New Dimension to Principal Components Analysis

October 27, 2011
By
A New Dimension to Principal Components Analysis

In general, the standard practice for correcting for population stratification in genetic studies is to use principal components analysis (PCA) to categorize samples along different ethnic axes.  Price et al. published on this in 20...

Read more »

Pair trading strategy : how to use "PairTrading" package

October 25, 2011
By
Pair trading strategy : how to use "PairTrading" package

Mr.Ishikawa(my old friend) and I developed "PairTrading" package, and uploaded it on CRAN.This article shows you how you can use it.The pair trading is a market neutral trading strategy and gives traders a chance to profit regardless of market conditions. The idea of this strategy is quite simple. 1 : Select two stocks(or any assets) moving similarly 2 : Short...

Read more »

Principal component analysis : Use extended to Financial economics : Part 2

October 22, 2011
By

My previous post talked about how we can employ PCA on the data for multiple stock returns to reduce the number of variables in explaining the variance of the underlying data. But the idea was greeted with skepticism by many. A caveat to the applicatio...

Read more »

R Tools for FEC Campaign Finance Disclosure Data

October 17, 2011
By
R Tools for FEC Campaign Finance Disclosure Data

For my first contribution to the blog, I wanted to make some kind of enlightening visualization of campaign finance disclosure data from the Federal Election Commission’s website. It looks like they’re working on some new, easy-to-use data dumps here, but … Continue reading →

Read more »

Principal component analysis : Use extended to Financial economics : Part 1

October 15, 2011
By
Principal component analysis : Use extended to Financial economics : Part 1

While working for my Financial economics project I came across this elegant tool called Principal component analysis (PCA)which is an extremely powerful tool when it comes to reducing the dimentionality of a data set comprising of highly correlated var...

Read more »

Tricks I learned today #1: as.integer() on factor levels

October 12, 2011
By

I normally work with full numerical data, not categorical data. R, when using read.csv() seems to recognize such categories and marks the column as to have factor levels. This is useful indeed. However, I wanted to make a PCA biplot on this data, so wa...

Read more »

Accessing and plotting World Bank data with R

September 25, 2011
By
Accessing and plotting World Bank data with R

Over the past couple of days I played around with the data sets of the World Bank, and I have to admit that I am blown away by it. It is amazing, to see what is available on their web site. It is worth visiting their Data Visualisation Tools page. It i...

Read more »

Examples on Clustering with R

August 25, 2011
By
Examples on Clustering with R

R code examples on various clustering techniques are available as “Clustering in R” in Chapter 4 of R & Bioconductor Manual by Thomas Girke, UC Riverside. It provides R examples on - Hierarchical Clustering, including tree cutting/coloring and heatmaps, - … Continue reading →

Read more »

Statistical Analysis Functions in R

August 20, 2011
By

Lately, I've been using statistical tests on a daily basis. I've noticed that I have to format my data the same way in order to get it into R (tab-delimited flat file essentially). Every other change in order to prep that data structure for any sort of...

Read more »