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 Description
Stem-and-Leaf Plot:  A graphical method used to represent ordered numerical data. Once the data are ordered, the stem and the leaves are determined. Typically, the stem is all but the last digit of each data point and the leaf is that last digit.

A stem-and-leaf plot shows all the data values from a sample set. It was invented by John Tukey in the 1960's. John Tukey also invented the box-and-whisker plot in the 1970's.

Example of a stem-and-leaf plot:

Quality Ratings for Natural Peanut Butter:

 Stem Leaves 3 4 4 0 5 2 7 7 6 0 0 3 7 9 9 9 7 1 8 9

Key:
 3 4
means 34.

All the data can be recovered from this plot by putting the stems and leaves together:

34, 40, 52, 57, 57, 60, 60, 63, 67, 69, 69, 69, 71, 89.

Example of side-by-side stem-and-leaf plots:

Suppose we wanted to compare the quality ratings of natural and regular peanut butter. Since the quality ratings were made using the same scale, we can create side-by-side stem-and-leaf plots. This means that the stem will be the same for each type of peanut butter, and so it will be put in the middle of our plot. The leaves will go to the left and right of the stems. The leaves to the left will help represent the quality ratings of the natural peanut butter, and the leaves to the right will help represent the quality ratings of the regular peanut butter.

 Natural PB Leaves Stems Regular PB Leaves 1 1 2 3 3 6 9 3 3 1 1 3 4 4 5 0 4 0 0 3 5 6 9 2 7 7 5 4 4 0 0 3 7 9 9 9 6 0 1 7 6 9 8 3 3

Key:
 1 1
means 11

All the data can be recovered from this plot by putting the stems and leaves together:

Natural peanut butter quality ratings: 33, 40, 52, 57, 57, 60, 60, 63, 67, 69, 69, 69, 71, 89

Regular peanut butter quality ratings: 11, 23, 23, 26, 29, 31, 31, 33, 34, 34, 35, 40, 40, 43, 45, 46, 49, 54, 54, 60, 76, 83, 83

It may be hard to create a stem-and-leaf plot if you have a large amount of data. A histogram would then be an easier choice. The histogram, like the stem-and-leaf plot, shows the shape of the data, but unlike a stem-and-leaf plot, you can not recover the data from a histogram.