year 8 maths

655
11 a
Survey location
Height
graph (cm)
Weight
graph (kg)
Age graph
(years)
b It is possible. (Hint: Divide every number by the current
range.)
Primary school
classroom
Graph 4 Graph 7 Graph 6
Exercise 9H
b Answers will vary.
Exercise 9G
1 a 1, 2, 3, 5, 10 b 10 c 1 d 9
2 a 9 b 12 c 9 d 7
3 a 30 b 6 c 7 d 7
4 a i 6 ii 3 iii 2 iv 1
b i 11 ii 7 iii 8 iv 2
c i 18 ii 12 iii 11 iv 11
d i 17 ii 26 iii 25 iv 25
e i 32 ii 16 iii 15 iv 10
f i 40 ii 34 iii 30 iv 55
g i 102 ii 71 iii 83 iv 84
h i 91 ii 41 iii 31 iv 18
5 a 16.6 b 17.5 c 12
6 a Brent b Brent c Ali d Brent
7 a 8.4 b 8 c 8 d mean
8 43.5
Shopping centre Graph 8 Graph 2 Graph 9
Teachers, Graph 5 Graph 3 Graph 1
common room
9 a 2 b 4 c 12
d 25 e 2.1 f 4
10 a 12 b 2 c 0 saves
11 a {9, 11}; other solutions possible.
b {8, 10, 13}; other solutions possible.
c {0, 100}; other solutions possible.
d {0, 5, 5, 7, 8, 8.1, 8.9}; other solutions possible.
12 a three values; e.g. {5, 5, 8}
b yes; e.g. {0, 0, 5, 5, 5, 7, 20}
13 a mean: 7, median: 7.5, range: 12
b i increases by 5 ii increases by 5
iii no effect
c i doubles ii doubles iii doubles
d Yes; e.g. if the set were duplicated:
1, 1, 3, 3, 5, 5, 10, 10, 10, 10, 13, 13.
14 a 7 and 13 b 9, 10, 11
c They must be 8, 10 and 12.
15 Most frequent value makes sense even for categories
but ‘mean’ requires adding (numbers) ‘range’ requires
subtracting (numbers), and ‘median’ requires ordering
(numbers).
16 a range = 6, mean = 7.18 b range = 4, mean = 7.21
17 50.5
18 a i 4, 4, 4; other solutions possible.
ii 1, 4, 3, 9, 1; other solutions possible.
iii 2, 3, 8, 10, 10; other solutions possible.
iv 1, 2, 3, 4, 4, 16; other solutions possible.
1 a 8 b 1 c 7
2 a 4 b 9 c 5
3 a 5 b 12 c 7
4 a lower quartile b lowest
c sort (or order)
d median
e odd
f spread
5 a 4 b 10 c 5.5
6 a 3, 4, 5, 5, 6, 7, 8, 10 b 4.5
c 7.5 d 3
7 a 19 b 11 c 21 d 15
e 7 f 9.5 g 3.16 h 1.76
8 a 23 b 19 c 35 d 32
e 16.5 f 10.5 g 3.45 h 1.15
9 a 11 b 10.5 c 9 d 8
e 32 f 23 g 18 h 13
10 a 15 b 35 c Nathan d Gary
11 a 1.7 b 1.8 c Max
12 a i 9 ii 10
b i 4.5 ii 4.0
c Sara d Andy
13 a i 8 ii 4
b i 98 ii 4
c A single outlier greatly affects range whereas IQR is
unaffected.
14 96
15 a 10 b 4
c No, the range is the largest difference between two
numbers.
d Yes, for instance, for a set like 2, 2, 2, 6, 6, 6.
16 a no effect b range is doubled
17 The lower quartile is the number above the bottom quarter
of values and the upper quartile is the number below the top
quarter of values.
18 a 4 b 3
c It would stay the same.
d It would stay the same.
e i It would double.
ii It would double.
Exercise 9I
1 a 5 b 2
2 a 39 b 27 c 134
3 57
4 a 8, 9, 10, 11, 13, 15, 17, 18, 21, 24 b 10
c i false ii true iii true iv false
5 a range = 20, median = 17
b range = 31, median = 26
c range = 19, median = 40.5
Cambridge Maths NSW
Stage 4 Year 8 Second edition
ISBN 978-1-108-46627-1 © Palmer et al. 2018
Cambridge University Press
Photocopying is restricted under law and this material must not be transferred to another party.