New Job

I just moved to the Educational Testing Service, to work on their cRater project, which is like the famous eRater essay-grading project, except with more semantics, and for short answers instead of essays. I THINK the c stands for content, but it could stand for "constructed response", which is a psychometrics and educational testing thing. Learning fast, having fun, working with a great group of people. Note that the cRater link describes cRater as it was in 2004, not as it is now.

"You can observe a lot by just watching" Yogi Berra

While it isn't always easy, I can usually tell where people were raised as well as where they were born. Koreans raised in Los Angeles have a style completely different from those born in Seoul; the English, en masse, look different from the Scots, and it just takes one look at those wacky triangular eyeglasses for me to know that a young lady is either French or getting that way. In the same way, just by looking, I can pretty much diagnose the families waiting for the Newark to Gatwick flight. Here's one, prematurely greying father with John Lennon glasses, slightly older  mother with shoulder length hair, three blond boys with backpacks and crew cuts. I'm like, O.K. , he's British, she's American, all three boys born in the USA. Or, Asian looking father, fiftyish, no mother in the party, two young teen daughters, one classically Eurasian looking, the other blonder. Sure, I can do that: he's born in Hong Kong, but doesn't speak Cantonese well, one kid born in Shanghai, the other in canoe transit up the Amazon. Same father, I think, but the first girl's mother is definitely working as a dogcatcher in Evansville, Indiana, and the second one's mother once had that unfortunate accident with a hairnet and an avocado. Could these be the same person? Very likely, but I'm not infallible, while I know for sure that the father is part-time seal tamer and computer science professor, I can't be be sure whether he's a bigamist. It's just a matter of assessing the evidence.

I can also tell what language people speak, because the patterns of vowels and consonants shape the face. Turkish oral surgeons spend 47% of their time unsticking the tongue tip from the roof of the mouth. "Who put the gluten in this agglutinative language?", they cry. And did you know that Mick Jagger was raised Basque? His English accent is a fake: he stole it from a classmate at LSE, using 1960s recording technology and a hypnopaedic pillow. You don't get those lips from an Indo-European language, let me tell ya! Angela Lansbury is Swedish, and Dick van Dyke really is a cockney. As a young man Rex Harrison sang Wagner's Parsifal with Maria Callas in the Italian premiere at La Scala: the My Fair Lady thing is a front. Not many know that, but you can see all this in their faces.

Just by looking, I can tell whether your dog will develop cataracts (and whether your cat will develop doggeracts, should you care). Show me your friend's wardrobe, and I can predict the mean rainfall over the Andes for the next two weeks. Two glances inside your purse and I can diagnose your psychological problems to eight decimal places AND predict your fashion preferences. Just from your diet, I can tell you not only your height, weight and hat size but your views on a wide range of social issues and the three last digits of your social security number. If you were raised by wolves, I can tell. If you were kept locked in a cupboard by your neglectful parents, I will spot it, and be able to offer career advice, speech therapy and a range of inexpensive  after-care options. If your father married his half sister and you were raised by a vengeful dwarf in the forest, I will know, and be the first to offer you a place to lay your sword. And advise you on whether the local fire brigade is any use for your unknowingly genetically suspect purpose. But I'm not special, I think most people could do that, just by looking.

Tag clouds

How to do comparisons between machine learning schemes

Nice paper comparing 16 model selection and weighting schemes. Includes 58 benchmark datasets. The data analysis was done in the following way - for each dataset, rank the schemes. Then average the ranks. - use the Friedman test to test whether ranks are all equal ( - if ranks are not all equal, use the Nemenyi test (covered in papers by Demsar, Garcia et al  http://jmlr.csail.mit.edu/papers/volume9/garcia08a/ Ying Yang, Geoffrey I. Webb, Jesús Cerquides, Kevin B. Korb, Janice R. Boughton, Kai Ming Ting: To Select or To Weigh: A Comparative Study of Linear Combination Schemes for SuperParent-One-Dependence Estimators. IEEE Trans. Knowl. Data Eng. 19(12): 1652-1665 (2007), ISSN: 1041-4347 http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.134.8561

What probability is about

Just as formal logic is a tool for capturing intuitions about effective ways of reasoning probability is a tool for capturing effective ways of reasoning about uncertainty.  In logic, we are taught to proceed from premises to conclusions. We conclude  that "If every CSE graduate takes the exit exam  before graduating and Emily is a CSE graduate, then Emily must have taken the exam" because this matches the Modus ponens pattern .  The good thing about this is that if we trust Modus ponens and we believe that we have correctly mapped the English description of the conclusion onto the terms of the formula, we know that the argument is valid. Notice that this claim of validity is not affected by the truth or falsity of the premises. Even if Emily never was a CSE student, or even if some CSE students are in fact able to weasel out of taking the exit exam, the argument is still OK. Not, however, especially useful as a way of working out stuff about Emily: if we aren't sure about the assumptions, we can't be sure about the conclusion either. Aristotle hit on the idea of laying out a taxonomy of plausible ways of reasoning, then thinking, in the abstract, about which of these patterns of reasoning actually deliver valid arguments. This is a wonderful idea, because you can rely on the insights about the patterns of reasoning without having to be concerned about the truth or falsity of particular facts.

In the same way that logic is the study of patterns of true/false reasoning, probability is the study of patterns of reasoning in the face of uncertainty.

Why statisticians shouldn't write movie titles

Never Give a Sucker an Asymptotically Even Flip
The Variational Enigma
The Fisher King
Independence Day
Return to Monte Casino
The Man Who Measured the Bank at Monte Carlo
Between 99 and 103 Dalmatians
8.5 +/- 0.2
The Metropolis Method (void where prohibited by law)
Improper Priors go wild on Cancun

War reporting

Yesterday Wikileaks   posted a shocking video taken from an Apache helicopter in Iraq. It

Julian Assange, who founded Wikileaks, was interviewed about this. . He feels that the soldiers in the helicopter obviously committed a war crime, and that