325 search results for "evaluation"

Performing a non-local return in R

February 23, 2014
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Performing a non-local return in R

In most languages return is a statement, but in R it is a function (in fact R does not really have statements, it only has expressions). This function-like behavior of return is useful for figuring out the order in which operations are performed, e.g., the value returned by return(1)+return(2) tells us that binary operators are

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Bayes factor t tests, part 2: Two-sample tests

February 23, 2014
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Bayes factor t tests, part 2: Two-sample tests

In the previous post, I introduced the logic of Bayes factors for one-sample designs by means of a simple example. In this post, I will give more detail about the models and assumptions used by the BayesFactor package, and also how to do simple analyses of two- sample designs.See the previous posts for background: What is a...

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Revolution R Enterprise in the Amazon Cloud

February 12, 2014
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by Oliver Vagner, Cloud Solutions Lead Architect at Revolution Analytics Today, I am pleased to announce our new offering in the Amazon Web Services Big Data Marketplace – Revolution R Enterprise 7 for AWS. Of course, if you follow this blog, then you are quite familiar with Revolution R Enterprise (RRE) and what it brings to the table with...

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Unprincipled Component Analysis

February 10, 2014
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Unprincipled Component Analysis

As a data scientist I have seen variations of principal component analysis and factor analysis so often blindly misapplied and abused that I have come to think of the technique as unprincipled component analysis. PCA is a good technique often used to reduce sensitivity to overfitting. But this stated design intent leads many to (falsely) Related posts:

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Inaccurate results from microbenchmark

February 2, 2014
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Inaccurate results from microbenchmark

The microbenchmark package is a popular way of comparing the time it takes to evaluate different R expressions — perhaps more popular than the alternative of just using system.time to see how long it takes to execute a loop that evaluates an expression many times. Unfortunately, when used in the usual way, microbenchmark can give inaccurate

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Automatic time series forecasting in Granada

January 30, 2014
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In two weeks I am presenting a workshop at the University of Granada (Spain) on Automatic Time Series Forecasting. Unlike most of my talks, this is not intended to be primarily about my own research. Rather it is to provide a state-of-the-art overview of the topic (at a level suitable for Masters students in Computer Science). I thought I’d provide...

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Tuning optim with parscale

January 26, 2014
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I often get questions what is the use of parscale parameter in optim procedure in GNU R. Therefore I have decided to write a simple example showing its usage and importance. The function I test is a simplified version of estimation problem I had to sol...

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BMHE & BCEA get a shout in published paper

January 15, 2014
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BMHE & BCEA get a shout in published paper

Panagiotis Petrou has posted a link to a recent paper of his, which develops a cost-effectiveness analysis of a drug used as a second-line treatment of renal carcinoma. The analysis is based on a Bayesian Markov model. But (from an incredibly self...

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Machine Learning with R – Book Review

Machine Learning with R – Book Review

I have to admit it...I'm an R junkie...since the first time I started learning R...it has become an addiction to me...I try to solve every problem with R...which is obviously not the best way to go...but my rule of thumb is..."Try with R first...otherw...

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analyze the national immunization survey (nis) with r

January 6, 2014
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for twenty years now, the centers for disease control and prevention (cdc) has been random-digit-dialing american households to ask parents which vaccinations their little tykes have received.  and since vaccination history might not be at the for...

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