1. 15/01/2019 Starter L.O. To be able to
Draw a stem and leaf diagram from a list of data
Use a stem and leaf diagram to interpret data
Key Words
stem, leaf, key, discrete, averages, data
Starter

2. CONTENTS – Click to go to…
15/01/2019
CONTENTS – Click to go to…
DRAWING STEM AND LEAF
USING STEM AND LEAF

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DRAWING A STEM AND LEAF

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A stem and leaf diagram show ordered discrete data.
Each number is broken up into two parts. For example, you might split the number 23 into a stem of 2 and a leaf of 3
Your key would look like this...
Key:
= 23
So the stem tells us how many tens and the leaf tells us the units of each data value

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Stem and leaf
Data must be in order
Think about how you will split each number into a stem and a leaf
Put them into the diagram
Cross out each number as you add it
Space them out evenly
Don’t forget your KEY!

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Example
7, 16, 37, 45, 22, 37, 11, 4, 35, 29, 33
Key: 2 2 = 22 1 2 3 4
Tens 4 7
Units 1 6 2 9 3 5 7 7 5

8. 15/01/2019
Task – on your mini whiteboards, draw a stem and leaf diagram for the following data
12, 25, 42, 7, 15, 15, 24, 19, 5, 46, 36, 38, 27, 3, 26, 45, 33, 27, 24

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Stem-and-leaf diagrams are useful as they contain the same degree of accuracy as the original data.

10. 15/01/2019 Task – Put each set of data into a stem and leaf diagram
44, 39, 22, 29, 37,
21, 41, 30, 30, 27, 42
54, 54, 59, 61, 42, 50,
63, 47, 47, 60, 59, 56, 57 2 3 4
1, 2, 7, 9
0, 0, 7, 9
1, 2, 4 4 5 6
2, 7, 7
0, 4, 4, 6, 7, 9, 9
0, 1, 3
73, 72, 90, 92, 78,
102, 99, 73, 90, 100
9, 12, 3, 28, 3, 3, 3, 0,
11, 10, 5, 9, 29, 31, 1, 6 7 8 9
2, 3, 3, 8
0, 0, 2, 9 10
0, 2 1 2
0, 1, 3, 3, 3, 3, 5, 6, 9, 9
0, 1, 2,
8, 9 3

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Discussion – For the number below, can you think of how they could be represented on a stem and leaf? What would the key look like? Show me ideas on your mini whiteboards…
145
1.7

12. 15/01/2019
Task – draw a stem and leaf diagram to show one of these sets of data. Choose your level of challenge…
Easy
Medium
Hard

13. 15/01/2019
Stem-and-leaf diagrams can be used to compare two sets of data. The back-to-back stem-and-leaf diagram shown below compares the height of 15 boys and 14 girls from a form group.
A stem-and-leaf diagram comparing the heights of pupils in a form group
The diagram shows that the boys in the form group are typically taller than the girls. The heights of the boys are also more varied than the girls’ heights.

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USING A STEM AND LEAF

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We also need to be able to use a stem and leaf diagram to analyse the data that it represents.
What information do you think we might be able to find out from a stem and leaf diagram?
Key:
2 1 = 2.1

16. a) Calculate the median. b) Calculate the range.
15/01/2019
Example 4 5 6 7 8
5|2 = 52
a) Calculate the median.
b) Calculate the range.
= 63

17. a) Calculate the median. b) Calculate the range.
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Example 4 5 6 7 8
5|2 = 52
a) Calculate the median.
b) Calculate the range.
= 63 =
= 41

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Key:
2 1 = 2.1
This stem and leaf diagram shows the heights, to the nearest metre, of a number of trees:
ALL: How many trees were there in the sample?
MOST: What is the range of heights of the trees?
What is the modal height of tree?
SOME: What is the median tree height?

19. 15/01/2019
Task 1 2 3 4
This stem and leaf diagram shows data about the areas of some photographs in an old album.
Key 4
1 represents 41cm
a) Write down the number of photographs that have an area of 38cm2
b) What is the total number of photographs?
c) Work out the range of the areas of the photographs
d) What is the modal area of the photographs?

20. CLICK FOR SOLUTIONS… 15/01/2019
Task - How confident do you feel drawing and using stem and leaf diagrams? Choose SUPPORT, CORE or EXTENSION from the available worksheets…
CLICK FOR SOLUTIONS… 15
35 – 5 = 30
13 times 41
53 – 23 = 30
12 teachers
KEY
KEY 19
46 – 1 = 45
2 sentences 24
33 – 18 = 15
6/15 or 2/5
KEY
KEY

21. 15/01/2019
Calculate the median, mode and range for each stem-and-leaf diagram.

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Exam question

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Spot the errors!
The range of the data is 40
The median of the data is 25
The mode of the data is 8