Big Talk About Small Samples
Posted by News Fetcher on November 17 '14 at 04:30 PM
By samzenpus from
Slashdot's read-all-about-it department:
Bennett Haselton writes:
My last article garnered some objections from readers saying that the sample sizes were too
small to draw meaningful conclusions. (36 out of 47 survey-takers, or 77%, said that a picture
of a black woman breast-feeding was inappropriate; while in a different group,
38 out of 54 survey-takers, or 70%, said
that a picture of a white woman breast-feeding was inappropriate in the same context.)
My conclusion was that, even on the basis of a relatively small sample, the evidence was
strongly against a "huge" gap in the rates at which the surveyed population would consider
the two pictures to be inappropriate. I stand by that, but it's worth presenting
the math to support that conclusion, because I think the surveys are valuable tools when
you understand what you can and cannot demonstrate with a small sample. (Basically,
a small sample can present only weak evidence as to what the population average is,
but you can confidently demonstrate what it is not.)Keep reading to see what Bennett has to say.
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By samzenpus from
Slashdot's in-the-beginning department:
An anonymous reader writes
Scientists have discovered a meteorite that provides evidence that intense magnetic fields caused the formation of the solar system. A meteorite called Semarkona crashed in northern India in 1940 and is now being studied for signs of primordial magnetic fields. Lead researcher, Roger Fu, a planetary scientist at MIT says: "It's a very primitive meteorite, which means that since it formed about 4.5 billion years ago, not much has happened to it, this means it preserves the properties it had when it first formed, helping shed light on that time." From the article: "This meteorite is made up of mostly tiny round pellets known as chondrules, which formed droplets that quickly cooled in space. According to the study, the scientists focused on these chondrules that possessed iron-bearing minerals, known as dusty olivine crystals, and if they appeared to have a magnetic field present while they were cooling, then the magnetic properties of these crystals might have recorded the strength of the magnetic fields."Read Replies (0)