Example of Stem-and-Leaf Plot

A scientist for a company that manufactures processed food wants to assess the percentage of fat in the company's bottled sauce. The advertised percentage is 15%. The scientist measures the percentage of fat in 20 random samples. Previous measurements found that the population standard deviation is 2.6%.

As part of the initial investigation, the scientist creates a stem-and-leaf plot to evaluate the distribution.

Open the sample data, FatContent.MTW.
Choose Graph > Stem-and-Leaf.
In Graph variables, enter 'Percent Fat'.
Click OK.

Interpret the results

For each row, the number in the "stem" (the middle column) represents the first digit (or digits) of the sample values. The "leaf unit" at the top of the plot indicates which decimal place the leaf values represent.

The first row of the stem-and-leaf plot of Percent Fat has a stem value of 12 and contains the leaf values 3, 4, and 8. The leaf unit is 0.1. Thus, the first row of the plot represents sample values of approximately 12.3, 12.4, and 12.8.

Stem-and-leaf of Percent Fat N = 20 3 12 348 3 13 4 14 3 7 15 249 (5) 16 23359 8 17 19 6 18 257 3 19 12 1 20 0 Leaf Unit = 0.1