336 search results for "evaluation"

Using apply, sapply, lapply in R

December 18, 2012
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This is an introductory post about using apply, sapply and lapply, best suited for people relatively new to R or unfamiliar with these functions. There is a part 2 coming that will look at density plots with ggplot, but first I thought I would go on a tangent to give some examples of the apply family, as they...

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Matrix Algebra Useful for Statistics

December 16, 2012
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Matrix Algebra Useful for Statistics

I was having a conversation with an acquaintance about courses that were particularly useful in our work. My forestry degree involved completing 50 compulsory + 10 elective† courses; if I had to choose courses that were influential and/or really useful they would be Operations Research, Economic Evaluation of Projects, Ecology, 3 Calculus and 2 Algebras.

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Multisite, multivariate genetic analysis: simulation and analysis

December 13, 2012
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Multisite, multivariate genetic analysis: simulation and analysis

The email wasn’t a challenge but a simple question: Is it possible to run a multivariate analysis in multiple sites? I was going to answer yes, of course, and leave it there but it would be a cruel, non-satisfying answer. … Continue reading →

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Bridge hand distribution: simulation vs exact calculation

December 8, 2012
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Bridge hand distribution: simulation vs exact calculation

Recently I played bridge with my friends. Being frustrated with several consecutive poor hand distributions we asked ourselves a question what is the probability of having a hand good enough for a small slam. A well known rule of thumb is that you need...

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Function Closures and S4 Methods

December 4, 2012
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Function Closures and S4 Methods

This brief tutorial illustrates how to combine S4 object oriented capabilities with function closures in order to develop classes with built in methods. Thanks to Hadley Wickham for the great contribution of material and tutorials made available on the web and to Bill Venables and Stefano Iacus for their kind reviews. Regular … Continue reading →

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Data types part 4: Logical class

November 30, 2012
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Data types part 4: Logical class

First, an update:  A commentator has asked me to post my code so that it is easier to practice the examples I show here.  It will take me a little bit of time to get all of my code for past posts well-documented and readable, but I have uploa...

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Discovering the quality of portfolio decisions

November 26, 2012
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Discovering the quality of portfolio decisions

Performance analysis of an example portfolio. The portfolio We explore a particular portfolio during 2007.  It invests in S&P 500 stocks and starts the year with a value of $10 million.  Initially there are 50 names in the portfolio.  It also ends the year with 50 names but has up to 53 names during the … Continue reading...

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Peer-reviewed R packages?

November 22, 2012
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Peer-reviewed R packages?

Dear R-Users, a question: I am the author of the ‘qpcR’ package. Within this, there is a function ‘propagate’ that does error propagation based on Monte Carlo Simulation, permutation-based confidence intervals and Taylor expansion. For the latter I recently implemented a second-order Taylor expansion term that can correct for nonlinearity. The formulas are quite complex

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How Microsoft Can Use Windows 8 to Dominate the Tech Industry

November 9, 2012
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How Microsoft Can Use Windows 8 to Dominate the Tech Industry

Windows 95 transformed the PC software market and established Microsoft as the dominant player.  Can Microsoft do it again?  Can it use the release of Windows 8 to elevate its entire brand image?  More importantly to some of us, can Microsoft use statistical modeling to help it achieve its goal?Of course, the answer depends on what you mean by...

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finding meaningful clusters in phylogenetic trees or other hierarchical clusterings

November 8, 2012
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finding meaningful clusters in phylogenetic trees or other hierarchical clusterings

Phylogenetic trees are a specialization of hierarchical clustering which elegantly capture relatedness between observations, grouping like with like. Yet hierarchical clusterings have one common complaint, as compared to density/distribution based clustering, the ability to classify the data into different types. … Continue reading →

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