Children's construction of fair chances: Adjusting probabilities

A probability-adjustment task was presented to 6-14-year-old children. In 2 experiments, children had to generate equal probabilities by completing the missing beads in a target urn with 1 type of beads presented beside a full urn with both winning and losing beads. The results indicate that only at around the age of 13 did most students proportionally integrate the 2 dimensions (i.e., the numbers of winning and losing beads).