P.Mean: Main page for the P.Mean website (created 2008-06-21)

P.Mean Website (created 1997-12-22, reborn at this location 2008-06-21)

Welcome to the P.Mean website. Here are the most important links:

The most recent website entries (View all website entries for 2010, 2009, or 2008)

P.Mean: Finding duplicate records in a 19 million record database (created 2010-03-02). I was asked to help find duplicate records in a large database (19 million records). The suspected number of duplicates was suspected to be small, possibly around 90. My colleague's approach was running PROC FREQ in SAS on the "unique" id and then looking for ids that have a frequency greater than 1. That did not work--it took too long or it overloaded the system, or both. So I wanted to look at alternatives for identifying duplicate records that would do this more efficiently.
P.Mean: Is intuition real? (created 2010-02-25). Someone asked if intuition is real. My hunch is that intuition is may be real, but it is grossly overrated.
P.Mean: Abstract submitted to Missouri Regional Life Sciences Summit (created 2010-02-13). Yesterday, I submitted the following abstract for a poster session in the Missouri Regional Life Sciences Summit. I'll find out on Monday if it will be accepted. "Slipped deadlines and sample size shortfalls in clinical trials: a proposed remedy using a Bayesian model with an informative prior distribution."
P.Mean: Meta-analysis for a single mean estimate (created 2010-02-11). Someone noted that the usual meta analysis is carried out for the study on two treatment groups, usually for a difference in means. What if you had several studies estimating not a difference in means, but just estimates of a single mean. Could you conduct a meta-analysis in this situation?
P.Mean: Exponential interpolation (created 2010-02-11). Someone wanted an exponential interpolation formula. It's not quite a statistics question, but it caught my interest.
P.Mean: Fan page for The Monthly Mean (created 2010-02-11). I've been getting some advice about Facebook. One suggestion was to set up a "fan page". There are some differences between being a "friend" on Facebook and being a "fan".

Pages recently receiving major updates

P.Mean: The first three steps in selecting an appropriate sample size (created 2009-07-20). I got an email last week from a client wanting to start a new research project looking at relationships between parenting beliefs and childhood behaviors. The description of the sorts of things to examine was quite elaborate, and it ended with the question "how many families would we need to have any significant differences if they exist?" Unfortunately, all the elaborate information provided did not include the information I would need to answer this question. Justifying a sample size usually involves three steps.

Interesting articles, books, quotes, or websites added to this site recently. (View all interesting articles, books, quotes, and websites for 2010, 2009 or 2008)

Julie Rehmeyer. Florence Nightingale: The Passionate Statistician - Science News. Science News. 2008. Excerpt: "When Florence Nightingale arrived at a British hospital in Turkey during the Crimean War, she found a nightmare of misery and chaos. Men lay crowded next to each other in endless corridors. The air reeked from the cesspool that lay just beneath the hospital floor. There was little food and fewer basic supplies. By the time Nightingale left Turkey after the war ended in July 1856, the hospitals were well-run and efficient, with mortality rates no greater than civilian hospitals in England, and Nightingale had earned a reputation as an icon of Victorian women. Her later and less well-known work, however, saved far more lives. She brought about fundamental change in the British military medical system, preventing any such future calamities. To do it, she pioneered a brand-new method for bringing about social change: applied statistics." [Accessed February 23, 2010]. Available at: http://www.sciencenews.org/view/generic/id/38937/title/Math_Trek__Florence_Nightingale_The_passionate_statistician.
Garrett Watts, Splunk Inc. jQuery Sparklines. Excerpt: "This jQuery plugin generates sparklines (small inline charts) directly in the browser using data supplied either inline in the HTML, or via javascript. The plugin is compatible with most modern browsers and has been tested with Firefox 2+, Safari 3+, Opera 9, Google Chrome and Internet Explorer 6, 7 & 8. Each example displayed below takes just 1 line of HTML or javascript to generate. The plugin was written by Gareth Watts for Splunk Inc and released under the New BSD License." [Accessed February 10, 2010]. Available at: http://omnipotent.net/jquery.sparkline/.
Douglas G Altman. Confidence intervals for the number needed to treat. BMJ. 1998;317(7168):1309-1312. Excerpt: "The number needed to treat is a useful way of reporting results of randomised clinical trials. When the difference between the two treatments is not statistically significant, the confidence interval for the number needed to treat is difficult to describe. Sensible confidence intervals can always be constructed for the number needed to treat. Confidence intervals should be quoted whenever a number needed to treat value is given" [Accessed February 8, 2010]. Available at: http://www.bmj.com/cgi/content/full/317/7168/1309.
J. A C Sterne, I. R White, J. B Carlin, et al. Multiple imputation for missing data in epidemiological and clinical research: potential and pitfalls. BMJ. 2009;338(jun29 1):b2393-b2393. Excerpt: "Missing data are unavoidable in epidemiological and clinical research but their potential to undermine the validity of research results has often been overlooked in the medical literature. This is partly because statistical methods that can tackle problems arising from missing data have, until recently, not been readily accessible to medical researchers. However, multiple imputation—a relatively flexible, general purpose approach to dealing with missing data—is now available in standard statistical software, making it possible to handle missing data semiroutinely. Results based on this computationally intensive method are increasingly reported, but it needs to be applied carefully to avoid misleading conclusions." [Accessed February 8, 2010]. Available at: http://www.bmj.com/cgi/data/bmj.b2393/DC1/1.
Anonymous. Statistical Graphics and more. Excerpt: "Statistical Graphics, Data Visualization, Visual Analytics, Data Analysis, Data Mining, User Interfaces - you name it" [Accessed February 5, 2010]. Available at: http://www.theusrus.de/blog/.

The most recent personal entries (View all personal entries)

Steve, Cathy, and Nicholas -- Nicholas the winter biker (created 2010-02-28). We wanted to go for a walk today, but Nicholas wanted to ride his bike instead. I'm not going to ride until it is at least 60 degree Fahrenheit. If Nicholas wants to brave the cold weather, I won't stand in his way. We walked while he biked. He was pretty good not to race too far ahead of Cathy and me. At the end of the bike ride, I snapped a few pictures as he circled around on our driveway and cul-de-sac.
Steve, Cathy, and Nicholas -- Nicholas meets Greg Mortenson (created 2010-02-19). On Thursday, December 17, 2009, Greg Mortenson came to town for a book signing. Nicholas has been a fan, having read the young reader's edition of Three Cups of Tea from cover to cover, so I arranged to get tickets.
Steve, Cathy, and Nicholas -- Nicholas the photographer (created 2010-02-19). I have one of those indestructible cameras (it goes underwater, can be dropped from seven feet, etc.) and once in a while I turn it over to Nicholas and let him shoot pictures of whatever he wants. Here are some examples. I cropped most of these pictures (just like I crop my own pictures), but they are otherwise untouched.
Steve, Cathy, and Nicholas -- Nicholas and fun in the snow (created 2010-02-06). I've already written about the big snow we had during Christmas break and the sledding that Nicholas did near Cleveland Chiropractic. We've had even more snow recently. On Saturday, January 30, we had an inch or so.
Steve, Cathy, and Nicholas -- Steve's hobbies (created 2010-01-31). My biggest non-work activity is taking care of Nicholas. He is quite a handful, in a fun way, of course. But I do have other hobbies that I should mention.

The most popular pages, excluding home page and various archive pages (last checked 2009-12-06)

This work is licensed under a Creative Commons Attribution 3.0 United States License. This page was written by Steve Simon and was last modified on 2010-03-02.