A crucial skill in scientific and everyday reasoning is the ability to interpret data. The present study examined how data features influence data interpretation. In Experiment 1, one hundred and thirty-three 9-year-olds, 12-year-olds, and college students (mean age = 20 years) were shown a series of data sets that varied in the number of observations and the amount of variance between and within observations. Only limited context for the data was provided. In Experiment 2, similar data sets were presented to 101 participants from the same age groups incrementally rather than simultaneously. The results demonstrated that data characteristics affect how children interpret observations, with significant age-related increases in detecting multiple data characteristics, in using them in combination, and in explicit verbal descriptions of data interpretations.