## Bounded Rationality and the Ellsberg Paradox

The Ellsberg paradox is a puzzle concerning human rationality. It postulates a scenario involving an urn with 90 balls inside - 30 red ones, while the remaining 60 can be yellow or black. A player gets to draw a ball from the urn, and receives a payoff dependent on the color …

## Topology of decisionmaking - are you secretly managing by metric?

Suppose you have a method of making decisions that doesn't suck - i.e., one that is objective, consistent, and never leaves you guessing about what to do. The mathematical field of topology provides a wonderful theorem - if you have a good decision process, it is equivalent to managing by metric.

Strength is a category theoretical property which is known to be boring - every `Monad` in `Hask` (and similarly `Scal`) satisfies it. The question arises - what about it's dual, Costrength? What would a Costrong Comonad look like? Is it interesting? It turns out the answer is no - every `Comonad` in `Hask`/`Scal` is `Costrong`. In this post I'll provide a brief tutorial on `Comonads` and show why every `Comonad` is also Costrong. You do NOT need to know much category theory to follow this post, but some familiarity with the everyday programming of Monads will be helpful.

## How to return an array of generic type, or "cannot find class tag for element type T"

I was recently writing some Scala code, and I wanted to return an array of generic type:

``````class Foo[+T] {
def someArray(size: Int): Array[T] = {
val result = new Array[T](size)
...
result
}
}
``````

This did not make Scala happy:

``[info] Compiling 1 Scala source to /home/stucchio/src/breeze/math …``

## Why a pro/con list is 75% as good as your fancy machine learning algorithm

I'm currently dating two lovely women, Svetlana and Elise. Unfortunately continuing to date both of them is unsustainable so I must choose one.

In order to make such a choice, I wish to construct a ranking function - a function which takes as input the characteristics of a woman and returns …

## Asymptotics of Evan Miller's Bayesian A/B formula

Earlier this year I published a blog post about a Baysian decision rule for choosing between two variations, each with a potentially different conversion rate. Later Evan Miller wrote a blog post computing an exact formula for evaluating it, rather than approximating the integral numerically. In this post I'm going …

## Easy Evaluation of Decision Rules in Bayesian A/B testing

Earlier this year I published a blog post about a Baysian decision rule (now dead link, but VWO now uses this for A/B testing and tech docs are here) for choosing between two variations, each with a potentially different conversion rate. The basic idea of the decision rule is …