1216 search results for "excel"

Negative Scalability Coefficients in Excel

May 12, 2009
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Negative Scalability Coefficients in Excel

Recently, several performance engineers, who have been applying my universal scalability law (USL) to their throughput measurements, reported a problem whereby their Excel spreadsheet calculations produced a negative value for the coherency parameter (...

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Statistics on Microsoft Excel

February 6, 2007
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Here is an interesting document on problems of using Microsoft Excel for statistical analysis. http://gcrc.ucsd.edu/biostatistics/Excel.pdf Technorati Tags: statistics, excel, microsoft

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Fast-track publishing using the new R markdown – a tutorial and a quick look behind the scenes

July 29, 2014
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Fast-track publishing using the new R markdown – a tutorial and a quick look behind the scenes

The new R Markdown (rmarkdown-package) introduced in Rstudio 0.98.978 provides some neat features by combining the awesome knitr-package and the pandoc-system. The system allows for some neat simplifications of the fast-track-publishing (ftp) idea using so called formats. I've created a new package, the Grmd-package, with an extension to the html_document format, called the docx_document. The formatter allows an almost...

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A Few Notes on UseR! 2014

July 25, 2014
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A Few Notes on UseR! 2014

It has been a month since the UseR! 2014 conference, and I'm probably the last one who writes about it. UseR! is my favorite conference because it is technical and not too big. I have completely lost interest in big and broad conferences like JSM (to me, it has become Joint Sightseeing Meetings). Karl has written two blog posts...

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Interactive visualization of non-linear logistic regression decision boundaries with Shiny

Interactive visualization of non-linear logistic regression decision boundaries with Shiny

(skip to the shiny app) Model building is very often an iterative process that involves multiple steps of choosing an algorithm and hyperparameters, evaluating that model / cross validation, and optimizing the hyperparameters. I find a great aid in this process, for classification tasks, is not only to keep track of the accuracy across models, »more

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Six of One (Plot), Half-Dozen of the Other

July 24, 2014
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Six of One (Plot), Half-Dozen of the Other

This is a guest post by Randy Zwitch (@randyzwitch), a digital analytics and predictive modeling consultant in the Greater Philadelphia area. Randy blogs regularly about Data Science and related technologies at http://randyzwitch.com. He’s blogged at Bad Hessian before here. For those of you with WordPress blogs and have the Jetpack Stats module installed, you’re intimately familiar… Continue reading →

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Making random draws from an arbitrarily defined pdf

July 23, 2014
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Making random draws from an arbitrarily defined pdf

I recently found myself in need of a function to sample randomly from an arbitrarily defined probability density function. An excellent post by Quantitations shows how to accomplish this using some of Rs fairly sophisticated functional approximation to...

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How to Choose an R-Trainer?

July 22, 2014
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How to Choose an R-Trainer?

by James Peruvankal There are plenty of options if you want to learn R and are looking for training: your college’s statistics department, massive open online courses like Coursera, Udacity, edX, Datacamp etc. SiliconANGLE recently published an article about top R-training companies. Let’s talk about how to choose a good R-trainer. First and foremost is technical competency in R...

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R and Meta-Analysis

July 17, 2014
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R and Meta-Analysis

by Joseph Rickert Broadly speaking, a meta-analysis is any statistical analysis that attempts to combine the results of several individual studies. The term was apparently coined by statistician Gene V Glass in a 1976 speech he made to the American Education Research Association. Since that time, not only has meta-analysis become a fundamental tool in medicine, but it is...

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Are Consumer Preferences Deep or Shallow?

July 8, 2014
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Are Consumer Preferences Deep or Shallow?

John Hauser, because no one questions his expertise, is an excellent spokesperson for the viewpoint that consumer preferences are real, as presented in his article "Self-Reflection and Articulated Consumer Preferences." Simply stated, preferences are e...

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