Beliefs underlying random sampling


Authors: 
Pollatsek, A., Konold, C. E., Well, A. D., & Lima, S. D.
Category: 
Volume: 
12
Pages: 
395 - 401
Year: 
1984
Publisher: 
Memory and Cognition
URL: 
RISE
Abstract: 

In Experiment 1, subjects estimated a) the mean of a random sample of ten scores consisting of nine unknown scores and a known score that was divergent from the population mean; and b) the mean of the nine unknown scores. The modal answer (about 40% of the responses) for both sample means was the population mean. The results extend the work of Tversky and Kahneman by demonstrating that subjects hold a passive, descriptive view of random sampling rather than an active balancing model. This result was explored further in in-depth interviews, wherein subjects solved the problem while explaining their reasoning. The interview data replicated Experiment 1 and further showed (a) that subjects' solutions were fairly stable-- when presented with alternative solutions including the correct one, few subjects changed their answer; (b) little evidence of a balancing mechanism; and (c) that acceptance of both means as 400 is largely a result of the perceived unpredictability of "random samples."

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