After last post's setting up for a simulation, it is now time to look how the models compare. To my disappointment with my simple simulations of assessors behavior the gain is minimal. Unfortunately, the simulation took much more time than I ...

A few days ago there was an interesting R based article by diffuseprior on the decline and fall in the quality of The Simpsons The author scraped results from GEOS, an online survey of TV programs, and applied the R package changepoint to offer an analysis of the show over time This seemed a candidate

I know I have already written a lot about technicalities in logistic regression (see for example: How robust is logistic regression? and Newton-Raphson can compute an average). But I just ran into a simple case where R‘s glm() implementation of logistic regression seems to fail without issuing a warning message. Yes the data is a Related posts:

Integrating Documentation and Calculation Integrating Documentation and Calculation This post is a first in that I've authored it using RStudio. I would guess most people who work in computational finance or quantitative risk are at least familiar with R. Unfortunately R as...

by Thomas Dinsmore On April 26, SAS published on its website an undated Technical Paper entitled Big Data Analytics: Benchmarking SAS, R and Mahout. In the paper, the authors (Allison J. Ames, Ralph Abbey and Wayne Thompson) describe a recent project to compare model quality, product completeness and ease of use for two SAS products together with open source...

Tree methods such as CART (classification and regression trees) can be used as alternatives to logistic regression. It is a way that can be used to show the probability of being in any hierarchical group. The following is a compilation of many of the key R packages that cover trees and forests. The goal here

Every once in a while I encounter a problem that requires the use of calculus. This can be quite bothersome since my brain has refused over the years to retain any useful information related to calculus. Most of my formal training in the dark arts was completed in high school and has not been covered

Revolution R Enterprise 6.2 is now available, and includes many new features that enhance the performance, scalability and enterprise readiness of R. On May 1, product manager Thomas Dinsmore will give an overview of the new features in a 30-minute webinar. You can register for the webinar (and the post-webinar slides and replay) at the link below. Revolution Analytics...

I was trying to change few levels in my factor variable by simply coercing characters on that factor variable but it dint seem to work. data(iris)iris$Species <- rep("Random", 71) ## Warning: invalid factor level, NAs generated iris$Species ## setosa ...