Big Talk About Small Samples 246
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.
