Stem-and-Leaf Diagrams

· When to use: Numerical data set with a small to moderate number of observations

· How to Construct

1.Select one or more leading digits for the stem values. The trailing digits (or sometimes jut the first one of the trailing digits) become the leaves.

2.List possible stem values in a vertical column.

3.Record the leaf for every observation beside the corresponding stem value.

4.Indicate the units for stems and leaves someplace in the diagram

· What to Look for

A representative or typical value in the data set;

The extent of spread about such a value;

The presence of any gaps in the data;

The extent of symmetry in the distribution of values;

The number and location of peaks;

The presence of any outliers.