Learning goals: Teacher Facing Choose which measure of center to use to describe a given data set and justify (orally and in writing) the choice. Explain (orally) that the median is a better estimate of a typical value than the mean for distributions that are not symmetric or contain values far from the center. Generalize how the shape of the distribution affects the mean and median of a data set. Full lesson plan (warm-up, activities, synthesis, cool-down prompt) from 6.8 Data Sets and Distributions, Grade 6.