1. Stem-and-Leaf Plot
By Mr. Lang

2. What is a stem-and-leaf plot?
A T-chart that is used to show numeric data and the distribution of numbers

3. Why would I want to use one?
It displays a lot of numbers in a neater, cleaner, and organized way.
It makes it easier to see how spread out the numbers are
It is easier to identify outliers

4. Reading a Stem-and-Leaf Plot

5. Things you need to know…
Stems
The stems include the digits in the tens place and higher

6. Things you need to know…
leaves
The leaves are all digits from ONLY the ones place
The leaves need to be organized from least to greatest
You can have multiples of the same digit per line

7. Making a Stem-and-Leaf Plot

8. This stem-and-leaf plot shows points that students received on a science quiz.40 49 56 58 59 61 64 67 73 75 76 78 80 85 87 88 92 96
100
Stem
Leaves 4 9 9 5 6 8 9 6 1 4 7 7 7 7 3 5 6 8 8 5 7 8 9 2 6 10

9. Finding the Range, Mode, Median, and Mean

10. Range= biggest number – smallest number
40 is the smallest number 40 49 56 58 59 61 64 67 73 75 76 78 80 85 87 88 92 96
100
Stem
Leaves 4 9 9
100 – 40 = 60
The range for this data set is 60 points. 5 6 8 9 6 1 4 7 7 7 7 3 5 6 8
100 is the largest number 8 5 7 8 9 2 6 10
This stem-and-leaf plot shows points that students received on a science quiz.

11. Finding the Median (the middle number)
Start counting with this leaf! 40 49 56 58 59 61 64 67 73 75 76 78 80 85 87 88 92 96
100
Stem
Leaves
Leaf number 12… This is the halfway point! 4 9 9
I have 23 leaves. If I divided that in half, I would end up with This means that the 12th number is my median.
23 ÷ 2 =  the 12th number will be our median.
The twelfth number is 73. This is my median. 5 6 8 9 6 1 4 7 7 7 7 3 5 6 8 8 5 7 8 9 2 6 10
This stem-and-leaf plot shows points that students received on a science quiz.

12. Finding the Mode (the number that shows up most)
You have more 7s than 9s or 0s. That means 67 is your mode. 40 49 56 58 59 61 64 67 73 75 76 78 80 85 87 88 92 96
100
Stem
Leaves 4 9 9
For the mode, look at each row of leaves separately.
If you see more than one of a number, underline it.
After looking at all your rows, pick the underlined
number that has the most digits. 5 6 8 9 6 1 4 7 7 7 7 3 5 6 8 8 5 7 8 9 2 6 10
This stem-and-leaf plot shows points that students received on a science quiz.

13. Finding the Mean (the average)40 49 56 58 59 61 64 67 73 75 76 78 80 85 87 88 92 96
100
Stem
Leaves 4 9 9
To find the mean, you will be doing a combination of
Adding and dividing. 5 6 8 9 6 1 4 7 7 7 7 3 5 6 8 8 5 7 8 9 2 6 10
This stem-and-leaf plot shows points that students received on a science quiz.

14. Finding the Mean (the average)
We have 23 leaves.
Divide your sum by 23.
Stem
Leaves 4 9 9 5 6 8 9
1667
÷ 23 = 6 1 4 7 7 7 7 3 5 6 8
Mean:
Approximately 72.48 8 5 7 8 9 2 6 10