Anchoring is an usual process when estimating abilities in test equating. This is about analyzing standardized tests, while maintaining a predefined scale. For example, assume that you have a set of 60 items in your test. However, two test forms (named... [Read more...]

Please note that an earlier version of this post had to be retracted because it contained some content which was generated at work. I have since chosen to rewrite the document in a series of posts. Please recognize that this may take some time. Apologies for any inconvenience.   Logistic regression ... [Read more...]

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Data Community DC and District Data Labs are excited to be hosting an Introduction to R Programming workshop on Saturday, September 26th. Register before 9/12/2015 for an early bird discount!  [Read more...]

Rotational strategies on ETFs have been a common occurrence on this blog, and I have been using something similar for real life trading for about two years now. Readers of this blog may have also noticed concerns about the stability of the computations of such strategies. At the end it ... [Read more...]

by Antony Unwin University of Augsburg, Germany David Moore's definition of data: numbers that have been given a context. Here is some context for the finch dataset: Fig 1: Illustrations of the beaks of four of Darwin's finches from "The Voyage of the Beagle". Note that only one of these (fortis) ... [Read more...]

  By Aimee Gott,  R Consultant, Mango Solutions Over the last month I have found multiple reasons for needing to scrape web pages for information. This started out with wanting to create a simple database for a training course containing … Continue reading → [Read more...]

Clipping polygons is a basic GIS task. It involves removing unneeded polygons outside of an area of interest. For example, you might want to study all local authorities (LADs) in the Yorkshire and the Humber region but can only obtain shapefiles that contain all the LADs in the UK. Removing ... [Read more...]

A new blog post over at Pluralsight describes reasons R has been generating a great deal of interest in recent days:  http://blog.pluralsight.com/r-programming-language. [Read more...]

A new blog post over at Pluralsight describes reasons R has been generating a great deal of interest in recent days:  http://blog.pluralsight.com/r-programming-language. [Read more...]

It seems the summer is coming to end in London, so I shall take a final look at my ice cream data that I have been playing around with to predict sales statistics based on temperature for the last couple of weeks [1], [2], [3]. Here I will use the new ... [Read more...]

It seems the summer is coming to end in London, so I shall take a final look at my ice cream data that I have been playing around with to predict sales statistics based on temperature for the last couple of weeks [1], [2], [3].Here I will use the new brms (GitHub, ... [Read more...]