tag:blogger.com,1999:blog-10065122Wed, 12 May 2010 06:49:30 +0000http://www.stat.columbia.edu/~tzheng/tianblog/noreply@blogger.com (Tian)Blogger137125tag:blogger.com,1999:blog-10065122.post-9093199073409073949Fri, 22 Jan 2010 18:30:00 +00002010-01-22T13:40:41.460-05:00An example of Simpson's paradox. [Read more]This article was emailed to me from Jacob Weaver, an alumni of our department.http://www.stat.columbia.edu/~tzheng/tianblog/2010/01/wsj-article-when-combined-data-reveal.htmlnoreply@blogger.com (Tian)1tag:blogger.com,1999:blog-10065122.post-4482189214746796139Fri, 22 Jan 2010 18:14:00 +00002010-01-22T13:17:55.842-05:00Entrepreneurs in the social and real-time data sectors would do well to study up on Venrock’s Brian Ascher. At the spritely age of 43 with several big tech exits under his belt (Adify, DatAllegro, Unicru), the investor is bound to be a force in the global Silicon Valley for a while to come. He’s interested in startups that follow what he calls the "data-as-a-service" model: gather tons of data byhttp://www.stat.columbia.edu/~tzheng/tianblog/2010/01/entrepreneurs-in-social-and-real-time.htmlnoreply@blogger.com (Tian)0tag:blogger.com,1999:blog-10065122.post-4702362445085824316Thu, 06 Aug 2009 19:35:00 +00002010-01-22T14:13:26.836-05:00Here is an article from the NY Times that outlines the up-and-coming status of statisticians in today's world. Enjoy!http://www.stat.columbia.edu/~tzheng/tianblog/2009/08/ny-times-for-todays-graduate-just-one.htmlnoreply@blogger.com (Tian)0tag:blogger.com,1999:blog-10065122.post-5372809837704096865Fri, 10 Jul 2009 14:24:00 +00002009-07-10T10:42:26.572-04:00 This morning I received a pleasant surprise in my inbox. Taiyun Wei , a student from Hunan, China emailed me about his/her R package, corrplot. This package can produce a number of pretty "stylish" visualization of your correlation matrices. Next time I need to present such a matrix of mine, I may give it a make-over from the "wardrobe" of Taiyun's functions. More of Taiyun's art-like http://www.stat.columbia.edu/~tzheng/tianblog/2009/07/make-over-for-your-correlation-matrix.htmlnoreply@blogger.com (Tian)0tag:blogger.com,1999:blog-10065122.post-4776305189541178717Mon, 06 Jul 2009 17:26:00 +00002009-07-06T13:37:46.903-04:00WSJ.com published an article on "Rise and Flaw of Internet's Election-Fraud Hunters: Benford's Law, Which Tests Numbers for Authenticity, Might Detect Vote-Rigging but Can't Prove It" that describes how one can use the limited information in the election count data to possbly detect fraud. Because of the limited nature of the data, some "model" has to be assumed, which can be wrong in the first http://www.stat.columbia.edu/~tzheng/tianblog/2009/07/election-fraud-detection.htmlnoreply@blogger.com (Tian)0tag:blogger.com,1999:blog-10065122.post-9008997013122360785Wed, 17 Jun 2009 19:35:00 +00002009-06-17T16:06:41.116-04:00"Xiao-Li Meng took a humorous approach to the sore subject of handling rejections whenhe was part of a panel, “Reflections on Rejections,” sponsored by Harvard’s Bureau ofStudy Counsel (BSC). We publish his article here to amuse and comfort the many IMSmembers who have to deal with rejections of their research papers. ..."For full article, see page 16 of IMS Bulletin Vol 38 Issue 5.http://www.stat.columbia.edu/~tzheng/tianblog/2009/06/accepting-rejections-by-xiao-li-meng.htmlnoreply@blogger.com (Tian)4tag:blogger.com,1999:blog-10065122.post-2466508736522032452Sun, 22 Mar 2009 01:42:00 +00002009-03-21T21:42:36.814-04:00Recently I noticed a couple of good examples of observational studies that can be used in my future Intro Stats teaching.1) In the Parents magazine, it reported that a study found a positive association between the frequency and severity of heartburn during pregnancy of the mom and how much hair the newborn baby has. According to the study, about two thirds of women who reported to have modest tohttp://www.stat.columbia.edu/~tzheng/tianblog/2009/03/couple-of-good-examples-of.htmlnoreply@blogger.com (Tian)0tag:blogger.com,1999:blog-10065122.post-7602879556321737104Tue, 22 Jul 2008 15:05:00 +00002008-07-22T11:13:15.369-04:00New York Times published an article today on "Women Are Now Equal as Victims of Poor Economy". The whole article can be found here. I found the time plots used in this article is very interesting. It has some good graphing tactics: use of color/shade, for example and the Y axis is actually from 0-100%.http://www.stat.columbia.edu/~tzheng/tianblog/2008/07/up-and-downs-of-percentage-of-working.htmlnoreply@blogger.com (Tian)0tag:blogger.com,1999:blog-10065122.post-3765763407401526957Mon, 21 Jul 2008 21:15:00 +00002008-07-22T11:01:53.902-04:00"The Black Swan" is a best-seller by Nassim Nicholas Taleb, the author of another bigger best-seller "Fooled by Randomness." Both books received more than 300 reviews on Amazon.com. I flipped through the second book in the bookstore and thought it was an interesting book, especially for teaching statistics to curious and skeptical undergraduate students.Today, I stumbled over a special issue in http://www.stat.columbia.edu/~tzheng/tianblog/2008/07/black-swan.htmlnoreply@blogger.com (Tian)6tag:blogger.com,1999:blog-10065122.post-9107509378090906040Mon, 21 Jul 2008 20:38:00 +00002008-07-21T16:53:18.023-04:00This may be one of the most interesting articles from the president's column of AMSTAT news I have read recently. It is a reaction to an editorial of the Journal of American Medical Association that "impugning the integrity of medical science." As part of the proposed solution for the integrity problem in the pharmaceutical industry, it is suggested that clinical trial data collected by a http://www.stat.columbia.edu/~tzheng/tianblog/2008/07/solution-to-improve-integrity-in.htmlnoreply@blogger.com (Tian)0tag:blogger.com,1999:blog-10065122.post-362542123181325874Mon, 25 Feb 2008 17:38:00 +00002008-02-25T13:43:36.610-05:00In collaboration with Dr. Dimitris Anastassiou (EE, Columbia), we just published a paper on "Identification of gene interactions associated with disease from gene expression data using synergy networks" in BMC System Biology.http://www.stat.columbia.edu/~tzheng/tianblog/2008/02/identifying-gene-gene-interaction-that.htmlnoreply@blogger.com (Tian)0tag:blogger.com,1999:blog-10065122.post-5822432891179433211Tue, 19 Feb 2008 16:48:00 +00002008-02-19T11:56:28.642-05:00Here are some references on this technology for my own use.Global Identification of Human Transcribed Sequences with Genome Tiling Arrays Science 24 December 2004:Vol. 306. no. 5705, pp. 2242 - 2246DOI: 10.1126/science.1103388Paul Bertone,1* Viktor Stolc,1,2* Thomas E. Royce,3 Joel S. Rozowsky,3 Alexander E. Urban,1 Xiaowei Zhu,1 John L. Rinn,3 Waraporn Tongprasit,4 Manoj Samanta,2 Sherman http://www.stat.columbia.edu/~tzheng/tianblog/2008/02/tiling-arrays.htmlnoreply@blogger.com (Tian)0tag:blogger.com,1999:blog-10065122.post-5981943030232184926Tue, 19 Feb 2008 16:45:00 +00002008-02-19T11:47:56.161-05:00I always thought there was no function for standard deviation in R. Since in Splus, it was stdev() if I remember correctly. I never help.seached it. I only found out that there was one: sd().http://www.stat.columbia.edu/~tzheng/tianblog/2008/02/standard-deviation-function-in-r.htmlnoreply@blogger.com (Tian)2tag:blogger.com,1999:blog-10065122.post-6864805998793405854Tue, 13 Nov 2007 14:18:00 +00002007-11-13T09:23:00.757-05:00For a while, I have been using the setwd() command at the beginning of a project's code. This allows one to save data, graph, output easily to a project's result folder without typing long path names. Yesterday, I was using a contributed package in R that requires the access to R's temp directory. The exact location of this folder can be found out using the command tempdir(). It just happened http://www.stat.columbia.edu/~tzheng/tianblog/2007/11/temp-directory-and-working-director-of.htmlnoreply@blogger.com (Tian)1tag:blogger.com,1999:blog-10065122.post-6659259294767034504Mon, 12 Nov 2007 14:32:00 +00002007-11-12T09:36:26.506-05:00R graphical manuals (a nice collection of examples and codes)http://cged.genes.nig.ac.jp/RGM2/index.php?clear=allCodes from the book "R graphics"http://www.stat.auckland.ac.nz/~paul/RGraphics/rgraphics.htmlhttp://www.stat.columbia.edu/~tzheng/tianblog/2007/11/useful-websites-for-graphics-in-r.htmlnoreply@blogger.com (Tian)0tag:blogger.com,1999:blog-10065122.post-3219051988921509911Fri, 02 Nov 2007 23:24:00 +00002007-11-02T19:37:05.496-04:00Today, I need to permute many two-way tables of the same dimension (say 2 by 3) to carry out a test of independence. My data looks like a big matrix with each row corresponding to a two-way table (arranged by row). The permutation is just to draw a random 2 by 3 table given independence between the two dimensions, conditioning on the observed marginal distributions. I didn't find (or didn't have http://www.stat.columbia.edu/~tzheng/tianblog/2007/11/fast-permuting-r-by-c-two-way-tables.htmlnoreply@blogger.com (Tian)1tag:blogger.com,1999:blog-10065122.post-7639507545025002788Wed, 24 Oct 2007 13:12:00 +00002007-10-24T09:26:49.119-04:00Today, on CNN, it was said that some experts argued several epidemic consequences of global warming. One of them is tropical diseases are moving north. For example, malaria cases were reported in New Jersey.I found this claim is a little far-fetch. According to scientists, the temperature change due to global warming is about (1.33 ± 0.32 °F) during the last 100 years. The difference between the http://www.stat.columbia.edu/~tzheng/tianblog/2007/10/tropical-infectious-diseases-moving.htmlnoreply@blogger.com (Tian)0tag:blogger.com,1999:blog-10065122.post-8257465693989531588Mon, 17 Sep 2007 23:11:00 +00002007-09-17T19:23:36.686-04:00Andrey Rzhetsky (a collaborator of mine) called me today. Among many things we discussed, he told me that our recent paper on estimating genetic overlap from phenotype data (time at diagnosis) had attracted quite a bit of popularity. It was the 24th most read paper of PNAS for the month of July 2007. And it was covered in MIT technology review and the Wired Science blog, among many other more http://www.stat.columbia.edu/~tzheng/tianblog/2007/09/probing-genetic-overlap-among-complex.htmlnoreply@blogger.com (Tian)0tag:blogger.com,1999:blog-10065122.post-3774069813060866074Sun, 16 Sep 2007 18:55:00 +00002007-09-16T15:00:58.076-04:00As Li pointed out, I had the wrong memory. I never aced any of these courses in my school days. BUT, I should have GOOGLED!!! :) That saying was published on May 11th, 1978. However, it was not proposed by Deng Xiaoping, despite the common perception. Deng only publicized it a lot. This is again a good example of Stigler's law of eponymy.http://www.stat.columbia.edu/~tzheng/tianblog/2007/09/correction-chair-mao-didnt-say.htmlnoreply@blogger.com (Tian)0tag:blogger.com,1999:blog-10065122.post-8211909843695548315Fri, 07 Sep 2007 22:32:00 +00002007-09-07T18:56:05.844-04:00I did not grow as a generation fully influenced by Mao Zedong. Actually, several days after I was born, he passed away. However, we still got to study quite a number of his quotes. One of them is "practice is the only way to validate the truth" (pardon my unpolished interpretation). 实践是检验真理的唯一标准。I have never given this quote much thought before yesterday.Yesterday, I received an email regarding ahttp://www.stat.columbia.edu/~tzheng/tianblog/2007/09/chairman-mao-was-right.htmlnoreply@blogger.com (Tian)1tag:blogger.com,1999:blog-10065122.post-4072159393606944905Fri, 25 May 2007 20:51:00 +00002007-05-25T17:01:30.145-04:00Next time I go to visit some of my friends, I will pay more attention to their little black gaming devices, called PS3. It turns out the best computer processor of our times is used in it. It is the Cell Chip developed jointly by IBM, SONY and Toshiba. According to some very scientific study comparing the Cell Chip with conventionally designed chipset, the performance for chips with comparable http://www.stat.columbia.edu/~tzheng/tianblog/2007/05/i-want-playstation-3-for-research.htmlnoreply@blogger.com (Tian)4tag:blogger.com,1999:blog-10065122.post-9122344200891085304Tue, 22 May 2007 22:43:00 +00002007-05-22T18:44:39.694-04:00I came across this website that allows you to organize citations online. I think it is pretty neat. Especially it has Bibtex format right on the screen.http://www.stat.columbia.edu/~tzheng/tianblog/2007/05/citeulike.htmlnoreply@blogger.com (Tian)0tag:blogger.com,1999:blog-10065122.post-5744013625152240089Mon, 14 May 2007 15:58:00 +00002007-05-22T18:46:20.657-04:00Men are more likely to spend money on Mother's day than women (in both percentage and amount). This is a fact but this is also a nice example of "confounding" for intro stats. I heard about this in the news (people were joking about this as a "mom's boy" phenomenon) but can't find that exact news article today. I found the data on Mother's day 2005 (a pretty neat collection of numbers). Here is http://www.stat.columbia.edu/~tzheng/tianblog/2007/05/mothers-day-spending.htmlnoreply@blogger.com (Tian)tag:blogger.com,1999:blog-10065122.post-5056810631624210383Wed, 09 May 2007 12:03:00 +00002007-05-09T08:16:34.186-04:00Anderson Copper 360 is a show on CNN that gives in-depth coverage of current events. In one of its recent airing, Anderson Copper discussed a question occurred during the recent Republican presidential debate: "do you believe in evolution?" One of the candidates added after the poll that he believed in evolution and also believed in God when watching things such as the sunset at Grand Canyon. http://www.stat.columbia.edu/~tzheng/tianblog/2007/05/divided-opinion.htmlnoreply@blogger.com (Tian)0tag:blogger.com,1999:blog-10065122.post-6154821343372357874Mon, 30 Apr 2007 23:12:00 +00002007-04-30T19:33:23.401-04:00PLoS Computational Biology's "Ten Simple Rules" series are pretty nice guidelines, including:Bourne PE (2005) Ten simple rules for getting published. PLoS Comp Biol 1: e57. Bourne PE, Chalupa LM (2006) Ten simple rules for getting grants. PLoS Comp Biol 2: e12. Bourne PE, Korngreen A (2006) Ten simple rules for reviewers. PLoS Comp Biol 2: e110. Bourne PE, Friedberg I (2006) Ten simple rules for http://www.stat.columbia.edu/~tzheng/tianblog/2007/04/ten-simple-rules-for-making-good-oral.htmlnoreply@blogger.com (Tian)0