Excel: Chart – Stem & Leaf Plots

Quickly Communicating Data Points

While many charts communicate data trends effectively, they do not do show them efficiently.
In other words, if the user only requires a quick snap shot of the data, a verbose, heavy-graphic chart wastes valuable time on the part of the user when only a list of numbers will solve their need.

For this article, I will begin with a simple data set showing disease diagnoses for each groups across several years.

This data may be communicated to the user with fancy charts using graphics, but that requires the spend time discerning trends and reading the numbers.

Instead, I will illustrate how to use a simple table to communicate the same trends for the year 2000 without using graphic elements.

In a Stem and Leaf Plot, use a simple table with two columns. In the left column place the first digit of the numbers in the series. In this chart I’ve reserved the left column for “stem” numbers in the “tens” portion. Think of “stem” as in a tree.
For example, the first number on the left ‘2’ means “20.”
The right column is used for “leaf” or the remainder of the numbers use on the left.
Continuing the same example from the ‘2’ stem, the numbers “6 and 9” on the right are leafs for the ‘2’ stem and mean “26” and “29.”
Next, ensure you order the stems (left numbers) from least to greatest.
Finally, provide an example key below the table using one steam and leaf.

Also, the stems may be any power of 10. For example to communicate “206” the stem would be “20” and the leaf “6.” The key would state “20|6 = 206.”

Notice how the greater simplicity of this chart and less time it requires to understand the numbers.

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