year 8 maths

9I
Stem-and-leaf plots
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11 A group of boys and girls have their heights recorded in a back-to-back stem-and-leaf plot, shown
here.
Girls Stem Boys
10
11
6 3 1 12
8 4 3 2 13 8
7 6 5 4 0 14 3 4 7 9
6 4 1 15 0 1 2 4 6 8
2 0 16 2 3 6 8
3 17
14 7 means 147 cm
a State the range of heights for:
i boys ii girls
b Which gender has a bigger range?
c State the median height for:
i boys ii girls
d Which gender has the larger median height?
e Which year level do you think these boys and girls are in? Justify your answer.
f Describe how you might expect this back-to-back stem-and-leaf plot to change if it recorded
the heights of male and female Year 12 students.
12 A teacher has compiled her class’ recent test scores out of 50 as a stem-and-leaf plot. However,
some values are missing, as represented by the letters a, b, c and d .
Stem Leaf
1 5
2 4 5 a 6 7 9
3 b 0 1 5
4 2 8 c
5 d
3 1 means 31
a How many students took the test?
b How many students passed the test (i.e. achieved a mark of 25
or higher)?
c State the possible values for each of the missing digits a to d.
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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