Aug 15, 2013 — Visual: Plotting Model Complexity vs. Error — I recently purchased the new Elements of Statistical Learning (with Applications in R) by Witten, Hastie, Tibshirani, and James, and am completely taken with the beautiful plots in this book.  Of course I won’t redistribute my copy, and I’m not... Read more

Aug 14, 2013 — Optimization Functions — I wanted to compile a nice list of (general) optimization functions for different algorithms, mostly so I don’t need to look them up one by one.  If an optimization method isn’t appropriate, I’ll summarize how you make a classification.  I... Read more

Aug 13, 2013 — Kernel Methods — Kernel methods, most commonly described in relation to support vector machines, allow us to transform our data into a higher dimensional space to assist with the goal of the learning algorithm.  Specifically for SVMs, we are looking to define the... Read more

Aug 9, 2013 — The Gap Statistic — The gap statistic is a method for approximating the “correct” number of clusters, k, for an unsupervised clustering. We do this by assessing a metric of error (the within cluster sum of squares) with regard to our choice of k.... Read more