year 8 maths

649
4 a discrete numerical
b continuous numerical
c continuous numerical
d categorical
e categorical
f categorical
g discrete numerical
h discrete numerical
i continuous numerical
j continuous numerical
k continuous numerical
l discrete numerical
m continuous numerical
n discrete numerical
o categorical
p discrete numerical
q categorical
r categorical
5 a observation
b sample of days using observation or secondary source
records
c census of the class
d sample
e sample
f sample using secondary source data
g census (every 5 years this question appears on the
population census)
h census of the class
i sample
j results from the population census
k observation
l observation
m sample
n census
o sample
6 a secondary – a market research company
b secondary – department of education data
c primary data collection via a sample
d secondary source using results from the census
e secondary source using NAPLAN results or similar
7 a Proximity to the Indian Ocean makes first hand
collection of the data difficult.
b Too many people to ask and a sensitive topic means that
using the census results as your source would be better.
c Extremely large population makes primary data difficult
to collect.
d Sensitive topic might make student less keen to give
honest and reliable answers.
e Cultural issues and the different cultural groups that exist
in the community makes collection difficult.
8 The data is often collected by a market research company.
It is not always possible to know how the data is collected,
the areas it is collected from and whether there was a bias
introduced in the surveys.
Cambridge Maths NSW
Stage 4 Year 8 Second edition
9 a A population is the entire group of people but a sample is
a selection from within it.
b If the population is small enough (e.g. a class) or there is
enough time/money to survey the entire population (e.g.
national census).
c When it is too expensive or difficult to survey the whole
population, e.g. television viewing habits of all of NSW.
10 a The answers stand for different categories and are not
treated as numbers. They could have been A − E rather
than 1 − 5.
b i 1 = strongly disagree, 2 = somewhat disagree,
3 = somewhat agree, 4 = strongly agree.
ii 1 = poor, 2 = satisfactory, 3 = strong, 4 = excellent.
iii 1 = never, 2 = rarely, 3 = sometimes, 4 = usually,
5 = always.
iv 1 = strongly disagree, 2 = disagree, 3 = neutral,
4 = agree, 5 = strongly agree.
11 a Excludes people who have only mobile numbers or who
are out when phone is rung; could bias towards people
who have more free time.
b Excludes people who do not respond to these types of
mail outs; bias towards people who have more free time.
c Excludes working people; bias towards shift workers or
unemployed.
d Excludes anyone who does not read this magazine; bias
towards readers of Girlfriend.
e Excludes people who do not use Facebook; bias towards
younger people or people with access to technology.
12 a For example, number of babies at a local playground.
Other answers possible.
b Count a sample, e.g. just one floor of one car park.
13 It gives ownership and establishes trust where there may
not have been any. It also ensures a deeper understanding of
the process and need for honesty in the collection and use
of any data.
14 a Too expensive and difficult to measure television
viewing in millions of households.
b Not enough people – results can be misleading.
c Programs targeted at youth are more likely to be watched
by the students.
d Research required.
15 a Too expensive and people might refuse to respond if it
came too often.
b English as a second language can impact the collection
of data (simple, unambiguous English is required). Some
people from particular cultures may not be keen to share
information about themselves.
c Some people cannot access digital technologies and they
would be excluded from the results.
d Larger populations and a greater proportion of people in
poverty can make census data harder to obtain.
16 Different people are chosen in the samples. Larger,
randomly selected samples give more accurate guides.
ISBN 978-1-108-46627-1 © Palmer et al. 2018
Cambridge University Press
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