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The Simpler Derivation of Logistic Regression

Logistic regression is one of the most popular ways to fit models for categorical data, especially for binary response data. It is the most important (and probably most used) member of a class of models called generalized linear models. Unlike linear regression, logistic regression can directly predict probabilities (values that […]

Your Data is Never the Right Shape

One of the recurring frustrations in data analytics is that your data is never in the right shape. Worst case: you are not aware of this and every step you attempt is more expensive, less reliable and less informative than you would want. Best case: you notice this and have […]

What is a large enough random sample?

With the well deserved popularity of A/B testing computer scientists are finally becoming practicing statisticians. One part of experiment design that has always been particularly hard to teach is how to pick the size of your sample. The two points that are hard to communicate are that: The required sample […]

SQL Screwdriver

Note February 11, 2020: this articles is out of date, we suggest using the methods of Using PostgreSQL in R: A quick how-to instead. We discuss a “medium scale data” technique that we call “SQL Screwdriver.” Previously we discussed some of the issues of large scale data analytics. A lot […]

Must Have Software

Having worked with Unix (BSD, HPUX, IRIX, Linux and OSX), Windows (NT4, 2000, XP, Vista and 7) for quite a while I have seen a lot of different software tools. I would like to quickly exhibit my “must have” list. These are the packages that I find to be the […]