Monthly Archives: August 2013

GDAT Class October 14-18, 2013

August 25, 2013
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This is your fast track to enterprise performance analysis and capacity planning with an emphasis on applying R statistical tools to your performance data. Early-bird discounts are available for the Level III Guerrilla Data Analysis Techniques class O...

RSiteCatalyst Version 1.1 Release Notes

August 25, 2013
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RSiteCatalyst version 1.1 is now available on CRAN. Changes from version 1 include: Support for Correlations/Subrelations in the QueueRanked function Support for Current Data in all ‘Queue‘ functions Support Anomaly Detection for QueueOvertime and QueueTrended functions (example usage with ggplot2 graph) Decrease in wait time for API calls (from 5 seconds to 2 seconds) and extending RSiteCatalyst Version 1.1...

Non-linear regression in R

August 25, 2013
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Here is the link to the article: http://rpubs.com/hughes/7812 There you will discover how to simulate and fit: power function, Michaelis-Menten equation and sigmoid curves in R, the fit is done by least-square using the ‘nls’ function.Filed under: R and Stat Tagged: NLS, R

More REML exercise

August 25, 2013
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Last week I tried exercise 1 of the SAS(R) proc mixed with R libraries lme4 and MCMCglm. So this week I aimed for exercise 2 but ended up redoing exercise 1 with nlme.Exercise 2 results gave me problems with library lme4 and latter parts of the ex...

From SVG to probability distributions [with R package]

August 25, 2013
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$From SVG to probability distributions [with R package]$

Hey, To illustrate generally complex probability density functions on continuous spaces, researchers always use the same examples, for instance mixtures of Gaussian distributions or a banana shaped distribution defined on with density function: If we draw a sample from this distribution using MCMC we obtain a plot like this one: Clearly it doesn’t really look

The Wonders of foreach

August 25, 2013
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Writing code from scratch to do parallel computations can be rather tricky. However, the packages providing parallel facilities in R make it remarkably easy. One such package is foreach. I am going to document my trail of discovery with foreach, which began some time ago, but has really come into fruition over the last few

Using R in Used Car Search

August 24, 2013
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Recently I was looking to buy a used car. I was using the Edmunds website to estimate the true market value of a used car. It has a nice click through interface where it guides you to input make, model, … Continue reading →

Exporting Results of Linear Regression with Robust Standard Errors

August 24, 2013
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August 24, 2013
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It seems like I have been going south since the blog started, first with the politicians and then Chennai Express. So continuing that journey, this time around I am looking at a Madras Cafe to find out what the TwitterVerse has been talking about it. Now the process is pretty much similar to that of... Read More ...

Residuals from a logistic regression

August 23, 2013
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I always claim that graphs are important in econometrics and statistics ! Of course, it is usually not that simple. Let me come back to a recent experience. A got an email from Sami yesterday, sending me a graph of residuals, and asking me what could be done with a graph of residuals, obtained from a logistic regression ?...