2.  Stem-and-leaf plots make it very easy to determine the least and greatest values in a set of data.  Stem-and-leaf plots also make it easy to determine the median and mode of a set of data.  Let’s look at an example.

3. Suppose I measured the height of everyone (in centimeters) in my class and displayed that information on the stem-and-leaf plot shown below. 15 16 17 18 19 20 Stem 0 1 2 5 5 0 2 4 4 6 9 9 0 1 2 4 7 8 8 2 5 0 2 8 0 Leaf Can you determine the heights of the shortest and tallest person in the class? Can you determine the median and the mode of this set of data? Height (cm) 17|0 = 170 cm

4. Finding the smallest value(s) on a stem-and-leaf plot is easy. Start by locating the smallest stem, ant then locate the smallest corresponding leaf. Put them together and this gives you the smallest value. 15 16 17 18 19 20 Stem 0 1 2 5 5 0 2 4 4 6 9 9 0 1 2 4 7 8 8 2 5 0 2 8 0 Leaf Smallest stem Shortest Person = 150 cm Smallest leaf Height (cm) 17|0 = 170 cm

5. Finding the largest value(s) on a stem-and-leaf plot is also easy. Start by locating the largest stem, ant then locate the largest corresponding leaf. Put them together and this gives you the largest value. 15 16 17 18 19 20 Stem 0 1 2 5 5 0 2 4 4 6 9 9 0 1 2 4 7 8 8 2 5 0 2 8 0 Leaf Largest stem Largest leaf Tallest person = 200 cm Height (cm) 17|0 = 170 cm

6. Because the data on a stem-and-leaf plot is listed in ascending or descending order, the median of the set of data can be easily determined by counting leaves and determining the middle value. If the set of data happens to contain an even amount of numbers then take the mean of the two middle values to find the median. 15 16 17 18 19 20 Stem 0 1 2 5 5 0 2 4 4 6 9 9 0 1 2 4 7 8 8 2 5 0 2 8 0 Leaf If you count the number of leaves, you will find that there are 25. 13 is halfway between 0 and 25, therefore the 13 th leaf on the stem-and-leaf plot would represent the median value. Remember to start counting from the smallest or largest value. Median = 170 cm Height (cm) 17|0 = 170 cm

7. In order to find the mode of a set of data from a stem-and-leaf plot, simply look for which leaf is repeated the most. This value represents the mode of the set of data. Remember that you can have more than one mode. 15 16 17 18 19 20 Stem 0 1 2 5 5 0 2 4 4 6 9 9 0 1 2 4 7 8 8 2 5 0 2 8 0 Leaf There are 4 different modes in this set of data, they are: Modes = 155 cm / 164 cm / 169 cm / 178 cm Height (cm) 17|0 = 170 cm