Stem-and-Leaf Plots and Boxplots

When confronted with a raw, unordered list of seventy-five exam scores or a spreadsheet of daily temperatures, the human brain sees only a wall of meaningless digits. We instinctively crave structure. Yet, when we compress that data into a simple average, we strip away the rich texture of the original dataset—the clusters of excellence, the isolated struggles, the overall spread. The fundamental challenge of data analysis is finding a way to summarize information without completely destroying its essence. To solve this, the brilliant statistician John Tukey popularized elegant visual tools in the 1970s designed specifically to bridge the gap between raw numbers and meaningful visual patterns. Two of his most enduring contributions allow us to see both the forest and the trees of a dataset: the stem-and-leaf plot and the boxplot.