Stephen Senn: Blood Simple? The complicated and controversial world of bioequivalence (guest post)

June 5, 2014
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Stephen Senn: Blood Simple?  The complicated and controversial world of bioequivalence (guest post)

Blood Simple? The complicated and controversial world of bioequivalence by Stephen Senn* Those not familiar with drug development might suppose that showing that a new pharmaceutical formulation (say a generic drug) is equivalent to a formulation that has a licence (say a brand name drug) ought to be simple. However, it can often turn out to […]

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Identifying pathways for managing multiple disturbances to limit plant invasions

June 5, 2014
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Andrew Tanentzap, William Lee, Adrian Monks, Kate Ladley, Peter Johnson, Geoffrey Rogers, Joy Comrie, Dean Clarke, and Ella Hayman write: We tested a multivariate hypothesis about the causal mechanisms underlying plant invasions in an ephemeral wetland in South Island, New Zealand to inform management of this biodiverse but globally imperilled habitat. . . . We […] The post Identifying pathways for managing multiple disturbances to limit plant invasions appeared first…

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Know your data 15: the false promise of data correction

June 5, 2014
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It's a good thing that FTC is making some noise about regulating the snooping done by online services. (link) It's not a good thing that the measures described in the article ("tools to view, suppress and fix the information") do not solve the fundamental problem, and are likely counter-productive. What's the fundamental problem? Imagine a world in which you walk into your supermarket. When you check out, you are required…

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Approches Statistiques du Risque

June 5, 2014
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Approches Statistiques du Risque

Il semble que l’ouvrage approches statistiques du risque, édité par Jean Jacques Droesbeke, Myriam Maumy-Bertrand, Gilbert Saporta et Christine Thomas-Agnan soit finalement paru, selon Gilbert Saporta. Ou devraient paraître – au pire – dans les jours à venir (je le vois pas encore sur le site de Technip). Les 400 pages reprennent les mini-cours que nous avions fait aux Journées d’Etudes Statistique de 2010, au CIRM, avec Patrice Bertail, Anne-Laure Fougères,…

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Box plot, Fisher’s style

June 5, 2014
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Box plot, Fisher’s style

In a recent issue of Significance, I discovered an interesting – and amuzing – figure, about some box & beard plot, in Dr Fisher’s casebook: Beard the statistician in his den. In French, the box plot (introduced by John Tukey, not George Box, as discussed in a previous post) is popular under the name boîte à moustaches (box with a mustache, for a simple translation). > set.seed(2) > x=rnorm(500) > boxplot(x,horizontal=TRUE,axes=FALSE)…

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The Unavoidable Instability of Brand Image

June 5, 2014
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The Unavoidable Instability of Brand Image

"It may be that most consumers forget the attribute-based reasons why they chose or rejected the many brands they have considered and instead retain just a summary attitude sufficient to guide choice the next time."This is how Dolnicar and Rossiter con...

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Another Benefit of Publicly Version-Controlled Research

June 4, 2014
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I've been thinking quite a bit lately about why and how political scientists should publicly version control their research projects. By research projects, I mean data, manuscript, and code. And by publicly version control, I mean use Git to version-control and post a public GitHub repository, from the beginning of the project, so that other […]

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Data!

June 4, 2014
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Data!

The animated gif below (>>link) counts data transferred every second over the internet (sources?). Another (static) infographic by Cisco estimates that …Continue reading →

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Determining chemical concentration with standard addition: An application of linear regression in JMP – A Guest Blog Post for the JMP Blog

Determining chemical concentration with standard addition: An application of linear regression in JMP – A Guest Blog Post for the JMP Blog

I am very excited to announce that I have been invited by JMP to be a guest blogger for its official blog!  My thanks to Arati Mejdal, Global Social Media Manager for the JMP Division of SAS, for welcoming me into the JMP blogging community with so much support and encouragement, and I am pleased to […]

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All the Assumptions That Are My Life

June 4, 2014
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Statisticians take tours in other people’s data. All methods of statistical inference rest on statistical models. Experiments typically have problems with compliance, measurement error, generalizability to the real world, and representativeness of the sample. Surveys typically have problems of undercoverage, nonresponse, and measurement error. Real surveys are done to learn about the general population. But […] The post All the Assumptions That Are My Life appeared first on Statistical Modeling,…

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Yet another power-law tail, explained

June 4, 2014
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Yet another power-law tail, explained

At the next Boston Python user group meeting, participants will present their solutions to a series of puzzles, posted here.  One of the puzzles lends itself to a solution that uses Python iterators, which is something I was planning to get more f...

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Simulate lognormal data with specified mean and variance

June 4, 2014
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Simulate lognormal data with specified mean and variance

In my book Simulating Data with SAS, I specify how to generate lognormal data with a shape and scale parameter. The method is simple: you use the RAND function to generate X ~ N(μ, σ), then compute Y = exp(X). The random variable Y is lognormally distributed with parameters μ […]

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Machine Learning and Applied Statistics Lesson of the Day – How to Construct Receiver Operating Characteristic Curves

Machine Learning and Applied Statistics Lesson of the Day – How to Construct Receiver Operating Characteristic Curves

A receiver operating characteristic (ROC) curve is a 2-dimensional plot of the (the true positive rate) versus (1 minus the true negative rate) of a binary classifier while varying its discrimination threshold.  In statistics and machine learning, a basic and popular tool for binary classification is logistic regression, and an ROC curve is a useful way to assess the predictive accuracy […]

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Did you buy laundry detergent on their most recent trip to the store? Also comments on scientific publication and yet another suggestion to do a study that allows within-person comparisons

June 3, 2014
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Please answer the above question before reading on . . . I’m curious after reading Leif Nelson’s report that, based on research with Minah Jung, approximately 42% of the people they surveyed said they bought laundry detergent on their most recent trip to the store. I’m stunned that the number is so high. 42%??? That’s […] The post Did you buy laundry detergent on their most recent trip to the…

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The pleasure of walking

June 3, 2014
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The pleasure of walking

The proverb goes: walk before you run. My latest contribution to Harvard Business Review (link) makes the point that many websites can improve their user experience by focusing on simple personalization measures, like showing me my shirt size. Recommendation engines based on machine-learning algorithms still have ways to go. I ran across a number of obstacles in my recent travel, which again highlights the value of getting the basics down.…

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Post-Piketty Lessons

June 3, 2014
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The latest crisis in data analysis comes to us (once again) from the field of Economics. Thomas Piketty, a French economist recently published a book titled Capital in the 21st Century that has been a best-seller. I have not read … Continue reading →

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Video Tutorial – Useful Relationships Between Any Pair of h(t), f(t) and S(t)

Video Tutorial – Useful Relationships Between Any Pair of h(t), f(t) and S(t)

I first started my video tutorial series on survival analysis by defining the hazard function.  I then explained how this definition leads to the elegant relationship of . In my new video, I derive 6 useful mathematical relationships that exist between any 2 of the 3 quantities in the above equation.  Each relationship allows one quantity […]

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Skimming statistics papers for the ideas (instead of the complete procedures)

June 2, 2014
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Skimming statistics papers for the ideas (instead of the complete procedures)

Been reading a lot of Gelman, Carlin, Stern, Dunson, Vehtari, Rubin “Bayesian Data Analysis” 3rd edition lately. Overall in the Bayesian framework some ideas (such as regularization, and imputation) are way easier to justify (though calculating some seemingly basic quantities becomes tedious). A big advantage (and weakness) of this formulation is statistics has a much […] Related posts: Checking claims in published statistics papers Data Science, Machine Learning, and Statistics:…

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How does Practical Data Science with R stand out?

June 2, 2014
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How does Practical Data Science with R stand out?

There are a lot of good books on statistics, machine learning, analytics, and R. So it is valid to ask: how does Practical Data Science with R stand out? Why should a data scientist or an aspiring data scientist buy it? We admit, it isn’t the only book we own. Some relevant books from the […] Related posts: A bit of the agenda of Practical Data Science with R Data…

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Swallowing the Bitter Pill: England, the Premier League and the World Cup

June 2, 2014
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Swallowing the Bitter Pill: England, the Premier League and the World Cup

Discussions abound about England’s chances at the 2014 edition of the World Cup. For a country which has produced elite football players such as Gary Neville, John Terry and Paul Scholes (and yes, David Beckham), there isn’t a lot of optimism ...

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Collaborative lesson development with GitHub

June 2, 2014
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Collaborative lesson development with GitHub

If you're doing any kind of scientific computing and not using version control, you're doing it wrong. The git version control system and GitHub, a web-based service for hosting and collaborating on git-controlled projects, have both become wildly popu...

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Why we hate stepwise regression

June 2, 2014
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Haynes Goddard writes: I have been slowly working my way through the grad program in stats here, and the latest course was a biostats course on categorical and survival analysis. I noticed in the semi-parametric and parametric material (Wang and Lee is the text) that they use stepwise regression a lot. I learned in econometrics […] The post Why we hate stepwise regression appeared first on Statistical Modeling, Causal Inference,…

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On deck this week

June 2, 2014
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Mon: Why we hate stepwise regression Tues: Did you buy laundry detergent on their most recent trip to the store? Also comments on scientific publication and yet another suggestion to do a study that allows within-person comparisons Wed: All the Assumptions That Are My Life Thurs: Identifying pathways for managing multiple disturbances to limit plant […] The post On deck this week appeared first on Statistical Modeling, Causal Inference, and…

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