Stem and leaf plot
A stem and leaf plot organizes data by showing the items in order using stems and leafs.The leaf is the last digit on the right or the ones digit.The stem is the remaining digit or digits. Here is how to easily pull out the stem and the leaf:
For 12, 2 is the leaf and 1 is the stem. For 45.7, 7 is the leaf and 45 is the stem.
Basically, as you can see in the figure below, a straight vertical line is used. Then, we put all stems on the left and all leaves on the right.
How to construct a stem and leaf plot
We will now illustrate with three carefully chosen examples.
Example #1:
24, 10, 13, 2, 28, 34, 65, 67, 55, 34, 25, 59, 8, 39, 61
First, put this data in order
2, 6, 10, 13, 24, 25, 28, 34, 34, 39, 55, 59, 61, 65, 67
We will use 0, 1, 2, 3, 4, 5, and 6 as stems. The plot is displayed below:
A stem and leaf plot can help you quickly identify how frequently data occur. For example, a quick look at the figure above will show that the number 34 occurs most often. It can also help you identify quickly the least and the greatest data value.
Example #2:
This time, the data is already in order
104, 107, 112, 115, 115, 116, 123, 130, 134, 145, 147
We will use 10, 11, 12, 13, and 14 as stems. The plot is displayed below:
Sometimes, it is useful to show leafs on both sides of the stem. Say for instance you teach algebra in two different classes.
You may in this case want to compare performance for the classes to see which class performed better.
Example #3:
Grade for class A: 60, 68, 70, 75, 84, 86, 90, 91, 92, 94, 94, 96, 100, 100
Grade for class B: 60, 60, 70, 71, 73, 73, 75, 76, 77, 84, 85, 86, 91, 92
The plot is displayed below:
A quick look at the graph and you will see that class A performed a lot better than class B.
Class B has more scores in the 70s than class A.
Class A has more scores in the 90s than class B.
This is one of the good features of stem and leaf plots. It helps you to quickly look at the graph and examine the data to make sound conclusion.