# Encyclopedia

January 17, 2012 |

Two posts ago we showed you the digit sound system for remembering numbers. This week we provide two computer programs to help you create mnemonics. [Read more...]

### You’ve got the whole world in your portfolio

December 29, 2011 |

A famous finance professor once told us that good diversification meant holding everything in the world. Fine, but in what proportion? Suppose you could invest in every country in the world. How much would you invest in each? In a market-capitalization weighted index, you'd invest in each country in proportion ... [Read more...]

### StatProb [wiki]

July 31, 2010 |

Via the [financial and technical] support of Springer, probability and statistics societies are launching a specialised wiki called StatProb. It operates as a wiki in that authors can submit short articles on any topic, with further co-authors joining in later to improve those articles, but with the contents guaranteed via ...

### Navigate the Bermuda Triangle of Mediation Analysis

July 6, 2010 |

MYTHS AND TRUTHS ABOUT AN OFTEN-USED, LITTLE-UNDERSTOOD STATISTICAL PROCEDURE If you go to a consumer research conference, you will hear tales of how experiments have undergone particular statistical rites: the attainment of the elusive crossover interaction, the demonstration of full mediation through Baron and Kenny’s sacred procedure, and so ...

### Tuesday’s child is full of probability puzzles

May 28, 2010 |

COUNTERINTUITIVE PROBLEM, INTUITIVE REPRESENTATION Blog posts about counterintuitive probability problems generate lots of opinions with a high probability. Andrew Gelman and readers have been having a lot of fun with the following probability problem: I have two children. One is a boy born on a Tuesday. What is the probability ... [Read more...]

### You won, but how much was luck and how much was skill?

May 4, 2010 |

In baseball, what are the chances the winner will win again against the same opponent the very next day? [Read more...]

### Get at least 12 observations before making a confidence interval?

April 14, 2010 |

How many observations should you have before constructing a confidence interval? [Read more...]

### Score with scoring rules

July 21, 2009 |

INCENTIVES TO STATE PROBABILITIES OF BELIEF TRUTHFULLY We have all been there. You are running an experiment in which you would like participants to tell you what they believe. In particular, you’d like them to tell you what they believe to be the probability that an event will occur. ... [Read more...]

### R gets some -E-S-P-E-C-T

January 12, 2009 |

NEW YORK TIMES STORY ON THE APPEAL OF R (click to view movie) It is no secret that Decision Science News is crazy about the R language for statistical computing. Find out why R is so great in this New York Times article. Then start to teach yourself R with ... [Read more...]

### R video tutorial number 2

October 2, 2007 |

READ TEXT FILES, RUN MODELS The Decision Science News R video tutorials continue with number 2. (If you missed that last one, you will want to watch R Video Tutorial Number 1 first.) The Goldstein pedometer dataset can be downloaded from http://www.dangoldstein.com/flash/Rtutorial2/pedometer.csv Topics covered this ... [Read more...]

### R video tutorial number 1

September 26, 2007 |

LEARN R BY JUST WATCHING For this week, Decision Science News has created a video tutorial on how to get started using the R Language for Statistical Computing. (The tutorial is best viewed in your browser’s full-screen mode, try pressing F11 in Windows). R is free and open source, ... [Read more...]