year 8 maths

20
656
6 a
Stem
Leaf
d
Stem
Leaf
1 1 2 3 4 4 5 7
2 0 4 8 9
3 1 2 3 5
39 1 5 6
40 1 2 4 5 6 6 8 9
41 1 2 3 3 5 6 7 8
b
c
d
7 a
Stem Leaf
2 0 2
3 9
4 5 7 9 9
5 1 2 2 3 5 6 8 8
Stem Leaf
1 6 6 8
2 1 4 8 9
3 1 2 3 5
4 1 8 9
5 0
Stem Leaf
1 1 2 4
2 7 9
3 2 7 8 8
6 0 0
7 3 8
8 1 7
Stem Leaf
8 0 4 5 6
9 0 6
10 1 4 5
11 0 3 4 4 5 9
42 0
8 a 2 b B c 1 d B e 1
f N g 2 h 1 i N
9 a 10 b 1 c 8 d 58 e 10
10 a i 49 years ii 36 years
b radio station 1
c i 33 to 53 years ii 12 to 32 years
11 a i 30 cm ii 52 cm b girls
c i 152 cm ii 144.5 cm d boys
e perhaps Year 6 or 7
f Both would have a smaller range and a higher median.
12 a 15 b 13
c a is 5 or 6, b is 0, c is 8 or 9, d is 0.
13 a i 30 ii 10
iii between 10 and 19 years old
iv between 31 and 49 years
v 18 vi between 18 and 28
b i true ii false iii true iv true
v false vi false
c Cannot determine how many people are exactly aged
40 years.
d close to 30 years
14 a Easier to compare sizes of different stems visually.
b Helps to notice trends and to calculate median.
15 a minimum: –29°C, maximum: 23°C
b i 5 ii 10 iii 11
c Because –05 and 05 are different numbers.
d −5.2°C
Exercise 9J
b
c
Stem Leaf
8 1 6
9 1 4 5 6 8
10 268
11 3557
12 0
Stem Leaf
15 5 7 8
16 2 5 7
17 3 4 8
18 1 4 4 5 7
19 2 2 3 3 6 9
Some answers may vary.
1 a surveying 1000 randomly selected people
b surveying 10 friends
2 a 2 5
3 a
Frequency
25
20
15
10
5
0
b 2000 c 300
0 1 2 3 4
Pets
b 400 c 1200
d More likely that people will have pets if near a vet clinic.
e Discussion point.
Cambridge Maths NSW
Stage 4 Year 8 Second edition
ISBN 978-1-108-46627-1 © Palmer et al. 2018
Cambridge University Press
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