2226 search results for "regression"

Modelling memory and news trajectories

February 6, 2013
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Modelling memory In the text below I present two models I've made to quantify and visualise the diverging trajectories of memory and news events, and conclude that linear regression may be used to test which model best describes the story. First, though, I contextualise this with an illustration from the...

The new Stan 1.1.1, featuring Gaussian processes!

February 6, 2013
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We just released Stan 1.1.1 and RStan 1.1.1 As usual, you can find download and install instructions at: http://mc-stan.org/ This is a patch release and is fully backward compatible with Stan and RStan 1.1.0. The main thing you should notice is that the multivariate models should be much faster and all the bugs reported for The post The...

Collinearity and stepwise VIF selection

February 5, 2013
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$Collinearity and stepwise VIF selection$

Collinearity, or excessive correlation among explanatory variables, can complicate or prevent the identification of an optimal set of explanatory variables for a statistical model. For example, forward or backward selection of variables could produce inconsistent results, variance partitioning analyses may be unable to identify unique sources of variation, or parameter estimates may include substantial amounts

Natura non facit saltus

February 5, 2013
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$\mathbb{E}_{\mathbb{P}}\left(\sum_{i=1}^N Y_i\right)=\mathbb{E}_{\mathbb{P}}(N) \cdot \mathbb{E}_{\mathbb{P}}(Y_i)$

(see John Wilkins’ article on the – interesting – history of that phrase http://scienceblogs.com/evolvingthoughts/…). We will see, this week in class, several smoothing techniques, for insurance ratemaking. As a starting point, assume that we do not want to use segmentation techniques: everyone will pay exactly the same price. no segmentation of the premium And that price should be related to...

Proposed techniques for communicating the amount of information contained in a statistical result

February 5, 2013
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$Proposed techniques for communicating the amount of information contained in a statistical result$

A couple of weeks ago, I posted about how much we can expect to learn about the state of the world on the basis of a statistical significance test. One way of framing this question is: if we’re trying to come to scientific conclusions on the basis of statistical results, how much can we update

Proposed techniques for communicating the amount of information contained in a statistical result

February 4, 2013
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$Proposed techniques for communicating the amount of information contained in a statistical result$

A couple of weeks ago, I posted about how much we can expect to learn about the state of the world on the basis of a statistical significance test. One way of framing this question is: if we’re trying to come to scientific conclusions on the basis of statistical results, how much can we update

"I don’t wanna grow up": Age / value relationships for football players

February 1, 2013
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Let's get back to the age-value relationship from my last post. I did some more plotting to see on which position this inversed U-shaped relationship is strongest. Please note, that I use a dataframe called eu.players throughout this post, which holds downloaded football player information from transfermarkt.de.But first, let us get back to the original graph.

Taking Expectations to the Next Level

January 31, 2013
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Higher Expectations I came across this post on Thursday and found it to be quite interesting. Clearly rental prices vary according to where you live. That isn't too surprising. I started thinking a bit more about it and thought that Boston and the nearby communities would have to...

January 30, 2013
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A Problem A major problem in secondary data analysis is that you didn't get to decide what data was collected. Lets say you were interested in how many times a student has read the Twilight books). Specifically, you want to know how effective the ads for...

January 30, 2013
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A Problem A major problem in secondary data analysis is that you didn't get to decide what data was collected. Lets say you were interested in how many times a student has read the Twilight books). Specifically, you want to know how effective the ads for...