agelman | July 11, 2010I realize that I haven't been posting much here. We had some plans to use the Applied Statistics blog for other purposes but it didn't really work out, so from now on you can go to my main blog for your statistical entertainment.
agelman | July 1, 2010I've been told that it's zombie day, so I thought I'd link to this research article by Gelman and Romero:
The zombie menace has so far been studied only qualitatively or through the use of mathematical models without empirical content. We propose to use a new tool in survey research to allow zombies to be studied indirectly without risk to the interviewers.
It's on Arxiv, so you know it's real.
agelman | June 23, 2010Maggie Fox writes:
Brain scans may be able to predict what you will do better than you can yourself . . . They found a way to interpret "real time" brain images to show whether people who viewed messages about using sunscreen would actually use sunscreen during the following week.
The scans were more accurate than the volunteers were, Emily Falk and colleagues at the University of California Los Angeles reported in the Journal of Neuroscience. . . .
About half the volunteers had correctly predicted whether they would use sunscreen. The research team analyzed and re-analyzed the MRI scans to…
agelman | April 27, 2010See discussion here. I've linked to it from here because ScienceBlogger and investigative journalist Tim Lambert has written some on the topic.
agelman | April 12, 2010Mark Buchanan wrote a cover article for the New Scientist on random matrices, a heretofore obscure area of probability theory that his headline writer characterizes as "the deep law that shapes our reality."
It's interesting stuff, and he gets into some statistical applications at the end, so I'll give you my take on it.
But first, some background.
About two hundred years ago, the mathematician/physicist Laplace discovered what is now called the central limit theorem, which is that, under certain conditions, the average of a large number of small random variables has an approximate normal (…
agelman | April 8, 2010Felix Salmon comments on a report that econ czar Larry Summers is likely to be leaving the government:
But if it's true, where is he leaving to? . . . "Wall Street consulting" is probably a polite way of saying "a return to DE Shaw", which happily paid Larry $5 million for one year of one-day-a-week work . . . The Summers exit could well be the most lucrative use of the revolving door yet seen in the short history of the Obama administration: if he was willing to work full time, Summers could command significantly more than the $10 million a year Citigroup paid Bob Rubin when Rubin left…
agelman | April 8, 2010John discusses an argument by Bruce Bartlett that it made sense for conservatives to support Hillary Clinton in 2008, based on the following reasoning:
Surveying the political landscape, I [Barttlett] didn't think the Republican candidate, whoever it might be, was very likely to win against whoever the Democratic candidate might be. Therefore I concluded that it was in the interest of conservatives to support the more conservative Democratic candidate . . . Hillary Clinton . . . probably would be governing significantly more conservatively than Obama.
I'm surprised to hear this, because I…
agelman | April 6, 2010Sociologists Dalton Conley and Emily Rauscher claim:
Using nationally-representative data from the [1994] General Social Survey, we [Conley and Rauscher] find that female offspring induce more conservative political identification. We hypothesize that this results from the change in reproductive fitness strategy that daughters may evince.
But economists Andrew Oswald and Nattavudh Powdthavee have found the exact opposite:
We [Oswald and Powdthavee] document evidence that having daughters leads people to be more sympathetic to left-wing parties. Giving birth to sons, by contrast, seems to make…
agelman | April 5, 2010A few months ago, Yu-Sung and I summarized some survey results from the 1993-1996 General Social Survey. 56% of respondents said they attended an amateur or professional sports event" during the past twelve months, and it turned out that they were quite a bit more Republican than other Americans but not much different in their liberal-conservative ideology:
Then, the other day, someone pointed me to this analysis by Reid Wilson of a survey of TV sports watchers. (Click the image below to see it in full size.)
The graph is very well done. In particular, the red and blue coloring (…
agelman | March 24, 2010Our story begins with this article by Sanjay Kaul and George Diamond:
The randomized controlled clinical trial is the gold standard scientific method for the evaluation of diagnostic and treatment interventions. Such trials are cited frequently as the authoritative foundation for evidence-based management policies. Nevertheless, they have a number of limitations that challenge the interpretation of the results. The strength of evidence is often judged by conventional tests that rely heavily on statistical significance. Less attention has been paid to the clinical significance or the practical…
agelman | March 24, 2010Deep in a long discussion, Phil writes, in evident frustration:
I don't like argument by innuendo. Say what you mean; how hard is it, for cryin' out loud?
Actually, it is hard! I've spent years trying to write directly, and I've often noticed that others have difficulty doing so. I always tell students to simply write what they did, in simple declarative sentences. (It can be choppy, that's fine: "I downloaded the data. I cleaned the data. I ran a regression" etc.) But it's really hard to do. As George Orwell put it, good prose is like a windowpane, but sometimes it needs a bit of…
agelman | March 23, 2010Kent Holsinger sends along this statistics discussion from a climate scientist. I don't really feel like going into the details on this one, except to note that this appears to be a discussion between two physicists about statistics. The blog in question appears to be pretty influential, with about 70 comments on most of its entries. When it comes to blogging, I suppose it's good to have strong opinions even (especially?) when you don't know what you're talking about.
P.S. Just to look at this from the other direction: I know next to nothing about climate science, but at least I…
agelman | March 22, 2010I came across this news article by Sharon Begley: Mind Reading Is Now Possible: A computer can tell with 78 percent accuracy when someone is thinking about a hammer and not pliers.
The article came out in 2008. I'm just wondering what's been happening since in this area.
agelman | March 21, 2010Felix Salmon gives the story. I haven't read the research articles, but it's an interesting story. As Salmon frames the book, it's Freakonomics-the-book vs. Freakonomics-style empirical analysis.
P.S. I'm assuming that both numbers above have been rounded to the nearest billion.
agelman | March 16, 2010Jeremy Miles pointed me to this article by Leonhard Held with what might seem like an appealing brew of classical, Bayesian, and graphical statistics:
P values are the most commonly used tool to measure evidence against a hypothesis. Several attempts have been made to transform P values to minimum Bayes factors and minimum posterior probabilities of the hypothesis under consideration. . . . I [Held] propose a graphical approach which easily translates any prior probability and P value to minimum posterior probabilities. The approach allows to visually inspect the dependence of the minimum…
agelman | March 12, 2010Sanjay Srivastava writes:
Below are the names of some psychological disorders. For each one, choose one of the following:
A. This is under formal consideration to be included as a new disorder in the DSM-5.
B. Somebody out there has suggested that this should be a disorder, but it is not part of the current proposal.
C. I [Srivastava] made it up.
Answers will be posted in the comments section.
1. Factitious dietary disorder - producing, feigning, or exaggerating dietary restrictions to gain attention or manipulate others
2. Skin picking disorder - recurrent skin picking resulting in skin…
agelman | March 8, 2010Brendan Nyhan links to this hilariously bad graph from the Wall Street Journal:
It's cute how they scale the black line to go right between the red and blue lines, huh? I'm not quite sure how $7.25 can be 39% of something, while $5.15 is 10%, but I'm sure there's a perfectly good explanation . . .
Follow the above link for more details. As Brendan notes, the graph says essentially nothing about the relation between minimum wage laws and unemployment ("Any variable that trended in one direction during the current economic downturn will be correlated with the unemployment rate among teens or…
agelman | March 7, 2010Brendan Nyhan passes along an article by Don Green, Shang Ha, and John Bullock, entitled "Enough Already about 'Black Box' Experiments: Studying Mediation Is More Difficult than Most Scholars Suppose," which begins:
The question of how causal effects are transmitted is fascinating and inevitably arises whenever experiments are presented. Social scientists cannot be faulted for taking a lively interest in "mediation," the process by which causal influences are transmitted. However, social scientists frequently underestimate the difficulty of establishing causal pathways in a rigorous empirical…
agelman | March 4, 2010This looks interesting:
Jean-Luc Thiffeault
Mathematics Department, University of Wisconsin - Madison
"Do fish stir the ocean?"
As fish or other bodies move through a fluid, they stir their surroundings. This can be beneficial to some fish, since the plankton they eat depends on a well-stirred medium to feed on nutrients. Bacterial colonies also stir their environment, and this is even more crucial for them since at small scales there is no turbulence to help mixing. It has even been suggested that the total biomass in the ocean makes a significant contribution to large-scale vertical…