I thought I'd cull some stories from track // microsoft that summarize the week's news: Steve Wozniak - famous for standing in line for Apple products, tweeted his intention to get into the smartphone game with a Lumia 900 The...

Following the question on dinner table permutations on StackExchange (mathematics) and the reply that the right number was six, provided by hardmath, I was looking for a constructive solution how to build the resolvable 2-(20,5,1) covering. A few hours later. hardmath again came up with an answer, found in the paper Equitable Resolvable Coverings by van [...]

Generalized linear models, linear mixed models, generalized linear mixed models, marginal models, GEE models. You’ve probably heard of more than one of them and you’ve probably also heard that each one is an extension of our old friend, the general linear model. This is true, and they extend our old friend in different ways, particularly in regard to the measurement level of the dependent variable and the independence of the…

Low volatility and minimum variance strategies have been getting a lot of attention lately due to their outperformance in recent years. Let’s take a look at how we can incorporate this low volatility effect into a monthly rotational strategy with a basket of ETFs. Performance Summary from Low Volatility Test in quantstrat Starting Equity: 100,000 … Continue reading →

Here is part 2 of my guide to using ggplot2. Scales Following on directly from the previous notes you can manually adjust the colours and shapes used in the chart if you don’t like the defaults, as shown in figure 1. … Continue reading ...

Last week I discussed how to fit a Poisson distribution to data. The technique, which involves using the GENMOD procedure, produces a table of some goodness-of-fit statistics, but I find it useful to also produce a graph that indicates the goodness of fit. For continuous distributions, the quantile-quantile (Q-Q) plot [...]

Two blog posts in the last 24 hours caught my attention. First was this post by Jeff Leek noting that there are many fields which are applied statistics by another name (and I’d add operations research to his list). The second is an excellent post on Cloudera’s blog on constructing case-control studies. It is generally excellent, but […]

Yesterday Simply Statistics linked to a paper with the provocative title Classifier Technology and the Illusion of Progress. I’ve only skimmed the article so far, but here are a few sentences that stood out. In particular, simple methods typically yield performance almost as good as more sophisticated methods, to the extent that the difference in performance [...]