1. 0-12 Stem and Leaf Plots Measures of Central Tendency
Goals:
Make and use a stem-and-leaf plot.
Find the mean, median and mode of data.
Eligible Content:
A / A

2. Vocabulary
Data – information, facts or numbers that describe something.
Bar Graph – compares different categories of data by showing each category as a bar whose length is related to the frequency.
Line Graph – a graph used to show how data changes over time.

3. Vocabulary
Stem and Leaf Plot – an arrangement of digits that is used to display and order numerical data.
Example:
Stem
Leaves 2 3 4 5
Key:
2|4 = 24

4. Important things to remember about a Stem and Leaf Plots:
Leaves are always only one digit.
Leaves are always in order from smallest to largest.
Leaves are NOT separated by commas!!
Stems are always in order from smallest to largest.
When listing the stems do NOT skip numbers.
There should always be a key!

5. Make a Stem and Leaf Plot
Ages of 24 patients at a health clinic:
25, 12, 30, 20, 15, 21, 16, 13, 18, 27, 43, 23, 19, 22, 20, 67, 53, 19, 25, 66, 35, 11, 20, 37
Stem
Leaves 1 2 3 4 5 6
Key:
1|2 = 12

6. Examples Pick random numbers from 0 – 50.
Use current grades.

7. Hey diddle diddle,
the cat and the fiddle, The cow jumped
over the moon. The little dog laughed
to see such a sport And the dish ran
away with the spoon!

8. Vocabulary Mean – average of the numbers in the data
To find mean:
Add all numbers and divide by how many there are!
Median – the middle number when the numbers are in order
To find median:
Put numbers in order and find the middle. If there are 2 numbers in the middle, find the mean between them.

9. Vocabulary Mode – the number that appears most often
Range – the difference between the largest number and the smallest number.

10. Find the mean, median and mode
Inches of snowfall in 14 towns:
8, 4, 7, 6, 5, 6, 7, 3, 8, 11, 10, 5, 8, 4
Mean:
total = 92 divided by 14 = 6.57
Median:
3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 8, 10, 11
Mode:
6.57 inches
6.5 inches
8 inches

11. Examples Find the mean, median, mode and range: 85, 90, 92, 91, 86, 90
89, 90, 90, 7
7, 8, 10, 12, 6, 8, 9, 8, 9, 11, 9, 8, 12
9, 9, 8, 6
60, 62, 57, 59, 58, 60, 55, 60, 56, 54
58.1, 58.5, 60, 8

12. Practice
Worksheet – “6.6 Practice A”

13. Homework
Pages P39-P40 #1-6
Page P45 #4,5 (make a stem and leaf plot only)