A Conspiracy of Statisticians, No Doubt

Statisticians reject global cooling

In a blind test, the AP gave temperature data to four independent statisticians and asked them to look for trends, without telling them what the numbers represented. The experts found no true temperature declines over time.
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The AP sent expert statisticians NOAA's year-to-year ground temperature changes over 130 years and the 30 years of satellite-measured temperatures preferred by skeptics and gathered by scientists at the University of Alabama in Huntsville.

Statisticians who analyzed the data found a distinct decades-long upward trend in the numbers, but could not find a significant drop in the past 10 years in either data set. The ups and downs during the last decade repeat random variability in data as far back as 1880.

Saying there's a downward trend since 1998 is not scientifically legitimate, said David Peterson, a retired Duke University statistics professor and one of those analyzing the numbers.

Identifying a downward trend is a case of "people coming at the data with preconceived notions," said Peterson, author of the book "Why Did They Do That? An Introduction to Forensic Decision Analysis."

Let's just remind ourselves what those NOAA data look like.

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Pros and Cons of the H1N1 Vaccine

From The Daily Show (Oct 15):

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Let's Get Something Straight About Ardi

Last week the journal Science published a raft of papers describing the fossil remains of Ardipithecus ramidus, an ape that lived 4.4 million years ago and that is more closely related to humans than to chimpanzees. The split between the lineages that (in retrospect) lead to humans and chimpanzees is thought to have occurred about 6 million years ago. So Ardi--as the fossil has been nicknamed--lived a million (or two) years after that split.

The common ancestor of humans and chimpanzees remains unknown because of a lack of fossils. In fact, it may surprise you to learn that until a few years ago there were no chimpanzee fossils either--and what has been found is just teeth. Presumably this is because they live in areas that are not conducive to fossilization.

Anyway, in the absence of fossils scientists have only been able to imagine what that common ancestor was like, and at times they have tried to make inferences based on chimpanzees. But it's easy to forget that chimpanzees are the product of 6 million years of evolution just as we are. Ardi gets us closer to that common ancestor, and based on her the discoverers argue that some of the traits of the common ancestor were a little more like humans and less like chimpanzees.

Unfortunately some of the reporting on Ardi contains confusing language--sometimes coming from the scientists that made the discovery. For example, one of the authors (C. Owen Lovejoy) has been quoted as saying that we didn't evolve from apes--apes evolved from us. First of all, humans are apes (just like we are mammals and primates). But more importantly, chimpanzees did not evolve from humans or vice versa. Each came from a common ancestor. Apparently that common ancestor has traditionally been thought to have been much like a chimpanzee. What Lovejoy means is that we can no longer use chimpanzees as a stand-in for the human-chimpanzee common ancestor because some chimpanzee characteristics evolved after the split.

The bottom line is that in light of Ardi, the authors argue that the common ancestor of humans and chimpanzees was a little more like humans, and a little less like chimpanzees, than previously thought.

I hope that helps. See Carl Zimmer's informative post, Ardipithecus: We Meet At Last for more.

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