194 search results for "heatmap"

Some Applications of Item Response Theory in R

January 11, 2015
By
Some Applications of Item Response Theory in R

The typical introduction to item response theory (IRT) positions the technique as a form of curve fitting. We believe that a latent continuous variable is responsible for the observed dichotomous or polytomous responses to a set of items (e.g., multipl...

Read more »

Top 77 R posts for 2014 (+R jobs)

January 7, 2015
By
Top 77 R posts for 2014 (+R jobs)

R-bloggers.com is 5 years old this month! In celebration, this post share links to the top 77 most read R posts of 2014 (+stats on R-bloggers, + top R jobs for the beginning of 2015)

Read more »

Mapping IPv4 Address (with Hilbert curves) in R

January 2, 2015
By
Mapping IPv4 Address (with Hilbert curves) in R

While there’s an unholy affinity in the infosec commuinty with slapping IPv4 addresses onto a world map, that isn’t the only way to spatially visualize IP addresses. A better approach (when tabluation with bar charts, tables or other standard visualization techniques won’t do) is to map IPv4 addresses into Hilbert space-filling curve. You can get a good feel...

Read more »

Contextual Measurement Is a Game Changer

December 22, 2014
By
Contextual Measurement Is a Game Changer

Adding a context can change one's frame of reference:Are you courteous? Are you courteous at work? Decontextualized questions tend to activate a self-presentation strategy and retrieve memories of past positioning of oneself (impression manag...

Read more »

A New Volatility Strategy, And A Heuristic For Analyzing Robustness

December 4, 2014
By
A New Volatility Strategy, And A Heuristic For Analyzing Robustness

This post is motivated by a discussion that arose when I tested a strategy by Frank of Trading The Odds … Continue reading →

Read more »

Trading The Odds Volatility Risk Premium: Addressing Data Mining and Curve-Fitting

November 19, 2014
By
Trading The Odds Volatility Risk Premium: Addressing Data Mining and Curve-Fitting

Several readers, upon seeing the risk and return ratio along with other statistics in the previous post stated that the … Continue reading →

Read more »

Introducing Stepwise Correlation Rank

October 27, 2014
By
Introducing Stepwise Correlation Rank

So in the last post, I attempted to replicate the Flexible Asset Allocation paper. I’d like to offer a thanks … Continue reading →

Read more »

Modeling Plenitude and Speciation by Jointly Segmenting Consumers and their Preferences

October 21, 2014
By
Modeling Plenitude and Speciation by Jointly Segmenting Consumers and their Preferences

In 1993, when music was sold in retail stores, it may have been informative to ask about preference across a handful of music genre. Today, now that the consumer has seized control and the music industry has responded, the market has exploded into more...

Read more »

Twitter Pop-up Analytics

October 20, 2014
By
Twitter Pop-up Analytics

IntroductionSo I've been thinking a lot lately. Well, that's always true. I should say, I've been thinking a lot lately about the blog. When I started this blog I was very much into the whole quantified self thing, because it was new to me, I liked the...

Read more »

TURF Analysis: A Bad Answer to the Wrong Question

September 29, 2014
By
TURF Analysis: A Bad Answer to the Wrong Question

Now that R has a package performing Total Unduplicated Reach and Frequency (TURF) Analysis, it might be a good time to issue a warning to all R users. DON'T DO IT!The technique itself is straight out of media buying from the 1950s. Given some number of...

Read more »