Stem and Leaf Diagrams

1

• Stem and Leaf Diagrams

Lesson Objective To be able to construct a Stem
and Leaf Diagram, and use it to find the mean,
median, mode and range of a set of data.
2

• What? Stem and Leaf Diagrams

Huh? It is a diagram that summarizes from 25 to
100 pieces of data while keeping all the
individual data points. It helps us by showing
us how data are spread .
How? Next Slide Please!
3
Stem and Leaf Diagrams
Here are the marks gained by 30 students in an
examination 63 58 61 52 59 65 69
75 70 54 57 63 76 81 64 68 59
40 65 74 80 44 47 53 70 81 68
49 57 61
4
Stem and Leaf Diagrams
Draw a line separating the ones digit (the digit
on the far right) from all other digits. For
example 53 would be 53 and 175 would be
175. 63 58 61 52 59 65 69
75 70 54 57 63 76 81
64 68 59 40 65 74 80 44
47 53 70 81 68 49 57 61
5
Stem and Leaf Diagrams
On the left side of the page, put the first
digits of each piece of data in numerical
order. 63 58 61 52 59 65 69
75 70 54 57 63 76 81
64 68 59 40 65 74 80 44
47 53 70 81 68 49 57 61
Stems
4 5 6 7 8
6
Stem and Leaf Diagrams
Go through each piece of data and put the
remaining digits in the proper row. 63 58
61 52 59 65 69 75 70 54
57 63 76 81 64 68 59 40
65 74 80 44 47 53 70 81
68 49 57 61
8
3
1
4 5 6 7 8
7
Stem and Leaf Diagrams
When all the marks are entered the diagram will
look like this
0 4 7 9
2 9 4 7 9 3 7
5 9 3 4 8 5 8 1
Leaves
5 0 6 4 0
8
1 0 1
3
1
4 5 6 7 8
8
Stem and Leaf Diagrams
2 3 4 7 7 8 9 9
Redraw the diagram so that the data in each row
are in order
0 4 7 9
1 1 3 3 4 5 5 8 8 9
0 0 4 5 6
0 1 1
4 5 6 7 8
9
Stem and Leaf Diagrams
2 3 4 7 7 8 9 9
0 4 7 9
1 1 3 3 4 5 5 8 8 9
Add a KEY
52 52
0 0 4 5 6
0 1 1
4 5 6 7 8
10
Stem and Leaf Diagrams

• Elements of a Good Stem and Leaf Plot
• On the left hand side of the page are the stems
  (the numbers without the last digit). These are
  the stems!
• A line separating the stems from the leaves!
• On the other side of the line are the last digits
  in the number. These are the leaves.
• A key is always included.

Oh, now I see!
11
Stem and Leaf Diagrams

• The stem leaf diagram below shows the masses in
  kg of some people in a lift.
• How many people were weighed?
• What is the range of the masses?
• Find the median mass.
• Find the mode(s).

(a) 16 people.
(b) 86 31 55 kg
(c) 56 kg
(d) 43 kg and 72 kg
Median is the mean of the 8th and 9th data
values.