Transcript Stem and Leaf Diagrams

Stem and Leaf Diagrams
Stem and leaf diagrams are a pictorial way of showing statistics
The important parts of a stem and leaf diagram are
The Title
The stem
The leaves in order starting from the stem
The number of items
The key
n = 20
Class Maths Marks
1 0 2 2 6 8
2
3 4 9 5 9
3
0 0 2 6 8 9 9
4
0 4 5
2 / 3 means a mark of 23
A group of students measured their pulse rates in beats per minute.
The results were.
66 69 62 58 74 56 67 72 61 62 59 60 72 58 63
Draw a Stem and Leaf diagram to show this
We need a title
Pulse rates (beats per minute)
5
86689889
We need the stems
We need the Leaves
6
6091227213260739
7
422224
We need to reorder the leaves
We need to write in n
We need the key
n = 15 6 / 2 means 62 beats per minute
A group of students were asked how much pocket money they get.
The results were.
£6.60 £6.90 £6.20 £5.80 £7.40 £5.60 £6.70 £7.20
£6.10 £6.20 £5.90 £6.00 £7.20 £5.80 £6.30
Draw a Stem and Leaf diagram to show this
Pocket money
Note this gives us the same
diagram as the previous
example. This shows the
importance of the title and
key.
5
6 8 8 9
6
0 1 2 2 3 6 7 9
7
2 2 4
n = 15 6 / 2 means £6.20
Draw Stem and Leaf Diagrams for the following sets of data
Speed in mph
The speed of cars, in mph, passing
police speed check
3 2 4 5 6 7 8 9
35 46 32 48 53 58 60 39 36
48 34 51 42 37 53 42 51 38
1 1 3 3 8
4 2 2 6 8 8
6 0
n = 18 4/3 means 43mph
Distance in metres
John took a note of how far, in
metres, he was able to hit a golf
ball
10 1 5 8
108 115 132 121 101 122 138
127 105 112 118 127 129 120
139 136 131 121 111 129 137
12 0 1 1 2 7 7 9 9
11 1 2 5 8
13 1 2 6 7 8 9
n = 21
12/3 means 123m
Stem and Leaf diagrams can be used to compare 2 sets of data.
To do this we draw a back to back stem and leaf diagram.
Maths marks for class 1A
8
0
Maths marks for class 1B
6 8 9
8 5 3
1
1 2 2 2 5 5 8
9 4 4 5 2 0
2
0 0 1 1 6 7
6 4 3 1 1 0
3
3 7 7
7 3 3
4
1
n = 19
3/2 means a mark of 32
n = 20
How many students in 1A had a mark of 31?
2
How many students in 1B had a mark of 12?
3
Which class appears to be best at Maths?
1A
Use the Back to Back Stem and Leaf Diagram to answer the questions
Books borrowed from the library
This week
Last week
2 0 1
4 1 3 1 5 6
7 4 4 3 4 0 4 5
1 0 5 2
4 1 6 3
n = 10
n = 10
2/0 represents 20 books
How many books were borrowed at level 3 this week
65
?
How many books were borrowed at level 4 last week
?
129
Which week was best for the library
How many books were borrowed last week altogether
This
? week
?
387