Reasoning from Data: The Effect of Sample Size and Variability on Children’s and Adults’ Conclusions

Interpretation of data is a critical part of scientific experimentation because it involves applying one’s background theoretical knowledge to the characteristics of the data. Though many researchers have examined the impact of background knowledge, few have considered the impact of the characteristics of the data in making decisions. In this study, we presented 3^rd graders, 6^th graders, and college undergraduates with a series of datasets that varied in sample size, consistency in data pairs and variability relative to the mean. We found that at all ages, participants showed sensitivity to sample size and whether or not there were overlapping data points in comparative datasets, but that there were age differences in the justifications used and in conclusions drawn from the data.