Lesson 1: Stem-and-Leaf Plots

Property

A stem-and-leaf plot is a way to organize numerical data that shows both the shape of the data distribution and the actual data values.
To create a stem-and-leaf plot, split each data value into two parts: the "stem" (usually the tens digit or higher place values) and the "leaf" (usually the ones digit).
List the stems vertically in order, then write the corresponding leaves horizontally next to each stem.
This type of graph allows us to identify clusters (data points together in a group), gaps (intervals without any reported values), peaks (stems where there are more leaves than for nearby stems), and outliers (values that are significantly different from the rest of the data).

Examples

Property

To create a stem-and-leaf plot:
(1) Order data from least to greatest;
(2) Choose stems (typically tens digits) and leaves (typically ones digits);
(3) Write stems vertically to the left of a vertical line;
(4) Write leaves for each stem to the right in numerical order;
(5) Include a key showing what the stem|leaf notation represents.

Examples

Property

A back-to-back stem-and-leaf plot displays two data sets side by side using a shared stem column in the middle, with leaves for the first data set on the left and leaves for the second data set on the right.

The leaves on both sides must be ordered from the stem outward (smallest to largest moving away from the stem).