January 2012

New R User Group in Cambridge, UK

January 31, 2012 | 0 Comments

Yet another new local R user group has launched this month, this time in Cambridge, UK. Cambridge RUG was created by data analyst Andrew Caines to promote the use of R in the Cambridge area. The group aims to encourage people try the R language, act as an advice centre ... [Read more...]

Example: Two Sample t-Test

January 31, 2012 | 0 Comments

The recovery time (in days) is measured for 10 patients taking a new drug and for 10 different patients taking a placebo. We wish to test the hypothesis that the mean recovery time for patients taking the drug is less than for those taking placebo. The...
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Example: One Sample t-Test

January 31, 2012 | 0 Comments

Using the stack loss dataset, test the hypothesis that the mean of the stackloss is equal to 20 versus a two-sided alternative. Solution:Codes:Output:Interpretation: With the p-value greater than the level of significance alpha at 0.05, then we la...
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Surfaces in ternary plots

January 31, 2012 | 0 Comments

In mixture experiments there is a constraint that the variables are the proportions of components that are mixed together with the consequence that these proportions sum to one. When fitting regression models to data from mixture experiments we may be interested in reprenting the fitted model with a surface plot. ... [Read more...]

ultimate R recursion

January 31, 2012 | 0 Comments

One of my students wrote the following code for his R exam, trying to do accept-reject simulation (of a Rayleigh distribution) and constant approximation at the same time: which I find remarkable if alas doomed to fail! I wonder if there exists a (real as opposed to fantasy) computer language ... [Read more...]

Collapse pasting in R

January 30, 2012 | 0 Comments

How do you take a vector in R, and paste the individual elements together?  Easy, a loop.  No, bad! **slap on the wrist**  Here’s an example why not.   So let’s start by concatenating a few character strings and showing some … Continue reading → [Read more...]

Using LaTeX, R, and Sweave to Create Reports in Windows

January 30, 2012 | 0 Comments

LaTeX is a typesetting system that can easily be used to create reports and scientific articles, and has excellent formatting options for displaying code and mathematical formulas. Sweave is a package in base R that can execute R code embedded in LaTe... [Read more...]

Explaining India’s miserable Test cricket performance in 2011/2012

January 30, 2012 | 0 Comments

Today when I reminded a friend not to lose hope in Indian cricket (after recent whitewash in England and Australia), another friend commented, प्रसून जी , यह भारतीय क्रिकेट है ..यहाँ पर हर विक्टरी दुसरे दिन पुरानी हो जाती है ...You have to perform at your best ... After all they are getting unexpected money. They should deliver the goods as per citizens expectations...My reply to my ... [Read more...]

Pre-conference tutorials announced for useR! 2012

January 30, 2012 | 0 Comments

The worldwide R user conference, useR! 2012, will take place this year June 12-15 in Nashville, Tennessee. In addition to the regular program of invited and contributed talks, a highlight of every useR! is the pre-conference tutorials: hand-on, half-day in-depth expert-led sessions with a focused on a specific area of methodology ... [Read more...]

the Art of R Programming [guest post]

January 30, 2012 | 0 Comments

(This post is the preliminary version of a book review by Alessandra Iacobucci, to appear in CHANCE. Enjoy [both the review and the book]!) As Rob J. Hyndman enthusiastically declares in his blog, “this is a gem of a book”. I would go even further and argue that The Art ... [Read more...]

The power of Rcpp

January 30, 2012 | 0 Comments

While ago I built two R scripts to track OMX Baltic Benchmark Fund against the index. One script returns the deviation of  fund from the index and it works fast enough. The second calculates the value of the fund every minute and it used to take for while. For example, ... [Read more...]

Getting Fancy with 3-D Scatterplots

January 30, 2012 | 0 Comments

R has some great functions for generating scatterplots in 3 dimensions. Two of the best are the scatter3d() function in John Fox’s car package, and the scatterplot3d() function in Uwe Ligges’ scatterplot3d package. In this post, we will focus on … Continue reading → [Read more...]
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