i don't understand stem and leaf plots
This site explains them very well.
http://www.purplemath.com/modules/stemleaf.htm
A stem and leaf plot is a simple way to organize and display data. It is especially useful for small to medium-sized data sets. The plot consists of two parts: the stem and the leaf.
Here's how to create a stem and leaf plot:
1. First, arrange the data in ascending order from the smallest to the largest value.
2. Separate each value into two parts: the stem and the leaf. The stem represents the digits to the left of the rightmost digit, and the leaf represents the rightmost digit.
3. Write the stems vertically from top to bottom, and place the corresponding leaves next to the corresponding stems.
4. If there are multiple data points with the same stem, write the leaf in increasing order next to the stem.
Here's an example to help you understand the process better. Let's say we have the following data set: 5, 7, 12, 15, 18, 21, 22, 25.
1. Arrange the data in ascending order: 5, 7, 12, 15, 18, 21, 22, 25.
2. Separate the values into stems and leaves:
- 5: stem = 5, leaf = 5
- 7: stem = 7, leaf = 7
- 12: stem = 1, leaf = 2
- 15: stem = 1, leaf = 5
- 18: stem = 1, leaf = 8
- 21: stem = 2, leaf = 1
- 22: stem = 2, leaf = 2
- 25: stem = 2, leaf = 5
3. Write the stems and leaves vertically:
- 1 | 2 5 8
- 2 | 1 2 5
Now you have a stem and leaf plot. It shows the distribution of the data set and preserves the individual values.
To read the plot, you can find the stem and then look at the corresponding leaves to determine the exact values in the data set. For example, in the above plot, the stem "1" has leaves 2, 5, and 8, indicating that the values are 12, 15, and 18.
Stem and leaf plots are helpful for quickly identifying the range, central tendency, and distribution of a data set.