Purple Math
Purplemath: Stem and Leaf Plots
Explains how to create a stem-and-leaf plot from a data set. Demonstrates how to format a clear stem-and-leaf plot.
National Council of Teachers of Mathematics
Nctm: Illuminations: State Names
Learners use multiple representations to display how many times the letters of the alphabet is used in a state name. Concepts explored: stem and leaf, box and whisker plots, histograms.