A stem-and-leaf plot displays data to show its shape and distribution. It is similar to a histogram. However, a stem-and-leaf plot shows exact data points, making the calculation of the mean, median, and mode much easier.
In a stem-and-leaf plot, each data value is split into a "stem" and a "leaf". The "leaf" is usually the last digit of the number, and the other digits to the left of the "leaf" form the "stem". The "leaf unit" indicates which decimal place the leaf values represent. For example, when the leaf unit is 1.0, the number 125 would be split as: stem 12, leaf 5. The number 8124 would be split as: stem 812, leaf 4.
Each row of the plot displays the count, stem, and leaf. The counts for rows before and after the median are cumulative. The count for a row before the median represents the total count for that row and the rows before it. The count for a row after the median represents the total count for that row and the rows after it.
The following stem-and-leaf plot shows the daily high temperatures for the month of June. The first row has a stem value of 6 and contains the leaf values 8, 9, and 9. The leaf unit is 1.0. Thus, the first row of the plot represents sample values of approximately 68, 69, and 69.