Embarrassingly I'm stumped on this...I have a program in R for looking at grade distributions in my class. I found something weird recently with my 'ifelse' processing. I noticed that my program seemed to be over counting Cs and under counting...
Blog Archives
Decomposition: The Statistics Software Signal
From: Decomposition: The Statistics Software Signal http://seanjtaylor.com/post/39573264781/the-statistics-software-signal"When you don't have to code your own estimators, you probably won't understand what you're doing. I'm not saying that you defini...
Data science = failure of imagination
From: http://www.r-bloggers.com/data-driven-science-is-a-failure-of-imagination/I think I like this distinction between Bayesian and Frequentist statistics: "we are nearly always ultimately curious about the Bayesian probability of the hypothesis ...
How John Deere uses R
HT: Revolution Analytics Very good discussion about real applied econometrics and analytics including the use of ARIMA models, decision trees, and genetic algorithms. He also has a very smart approach in his attitude toward big data and data s...
R Code for A Justification and Application of Eigenvector Centrality
Leo Spizzirri does an excellent job of providing mathematical intuition behind eigenvector centrality. As I was reading through it, I found it easier to just work through the matrix operations he proposes using R. You can find his paper her...
Nonnegative Matrix Factorization and Recommendor Systems
Albert Au Yeung provides a very nice tutorial on non-negative matrix factorization and an implementation in python. This is based very loosely on his approach. Suppose we have the following matrix of users and ratings on movies:
If we use the information above to form a matrix R it can be decomposed into two matrices...
Using SNA in Predictive Modeling
In a previous post, I described the basics of social network analysis. I plan to extend that example here with an application in predictive analytics. Let's suppose we have the following network (visualized in R)Suppose we have used the igraph package ...
An Introduction to Social Network Analysis with R and NetDraw
With the rise in the use of social media, data related to social networks is ripe for analysis using techniques from social network analysis and graph theory. According to International Network for Social Network Analysis, ‘Social network analysis is...
Time Series Intervention Analysis wih R and SAS
In a previous post, I worked through the theory behind intervention analysis. In his time series course, University of Georgia political science professor Jamie Monogan demonstrates how to implement intervention analysis in R. The following examp...
Regression via Gradient Descent in R
In a previous post I derived the least squares estimators using basic calculus, algebra, and arithmetic, and also showed how the same results can be achieved using the canned functions in SAS and R or via the matrix programming capabilities offered by ...
Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).
