Yes, that's the one, thanks. Since this isn't a public talk I won't identify the frequentist in question, but he was uncomfortable with the very idea of assigning a probability to an event that "either happened or didn't". Something about babies and bathwater comes to mind.
That said, he also described a very long and involved set of calculations that went into the figure, and pointed out that no effort was made to assign confidence bounds to any of it. I don't know of any claims about this paper in the press. I have two very trusted independent sources who haven't the slightest doubt that the Chicxulub impact was the dinosaur killer; I am not sure they care very much which deep space event sent that gift our way. I certainly can't get all that worked up about it. Although I'm a worrier by nature I have a hard time getting too alarmed by potential harm from Chicxulub Jr. While I am mentioning Chicxulub, it is amazing that life survived the event at all. That's based on the description I heard from gbeophysicist Sean Gulick of Texas recently, who is working this up as an outreach talk. Likely all remaining life descends from a few survivors deep within caves which were immune to the huge temperature swings. mt On 9/10/07, James Annan <[EMAIL PROTECTED]> wrote: > > Michael Tobis wrote: > > I'm at a conference with some statisticians at this moment. One talk > > today discussed a recent paper in Nature which alleged that the > > Chixculub meteor had a certain origin with probablity 90%. The gist of > > the talk was that the professional statistician was unable to ascribe > > enough meaning to the 90% claim to refute it. > > http://www.nature.com/nature/journal/v449/n7158/full/nature06070.html > > The paper itself is actually clear enough. If a particular event took > place as described, then it would have produced impacts at a much > greater rate than the background, such that any impact would with 90% > probability come from this event. I don't think it is unreasonable to > think about a single impact as a random sample from an "urn" of rocks > floating around in space. But on the face of it the research does not > justify the claims made in the press (or your phrasing above). > > > Global change isn't a drug trial and we can't round up 500 planets to > > give half of them CO2 and half a placebo to get a 99% refutation of > > the null hypothesis. We actually have to think, not just apply > > formulas. > > What I find interesting about it all is how little people care. It's not > as if I am the first person to think about it, indeed I am doing nothing > more than following a well-worn path (there are rants aplenty on this > general topic on the web). And yet...as Nature put it, "the concerns you > have raised apply more generally to a widespread methodological > approach" and therefore can safely be ignored. > > James > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups Global Change ("globalchange") newsgroup. Global Change is a public, moderated venue for discussion of science, technology, economics and policy dimensions of global environmental change. Posts will be admitted to the list if and only if any moderator finds the submission to be constructive and/or interesting, on topic, and not gratuitously rude. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/globalchange -~----------~----~----~----~------~----~------~--~---
