Description

Tendency for people to neglect that a larger sample size is more likely to approximate a population value.

Kahneman, D., & Tversky, A. (1982). On the study of statistical intuitions. Cognition, 11(2), 123–141.

Tversky, A., & Kahneman, D. (1974). Judgment under uncertainty: Heuristics and biases. Science, 185(4157), 1124–1131.

Items (2)

1. There are two hospitals in a city. In the big hospital, 45 children are born every day, and in the small hospital 15 children are born every day. On average, 50% of the children born are boys, but it varies from day to day. In which hospital do you think that it is most likely that more than 60% of the children born are boys in a specific day?

a. The big hospital
b. The small hospital

2. As you know, a game of squash can be played either to 9 or to 15 points. Holding all other rules of the game constant, if A is a better player than B, which scoring system will give A a better chance of winning?

a. The 9-point scoring system
b. The 15-point scoring system

Scoring

The biased response in the Hospital problem is "The big hospital" and the 9-point scoring system in the Squash problem.

Source

Toplak, M. E., West, R. F., & Stanovich, K. E. (2011). The Cognitive Reflection Test as a predictor of performance on heuristics-and-biases tasks. Memory & cognition, 39(7), 1275–1289.