year 8 maths

Semester review 2 599
7 A set of six scores is given as 17, 24, 19, 36, 22 and □ .
a Find the value of □ if the mean of the scores is 23 .
b Find the value of □ if the median of the scores is 22 .
c If the value of □ is 14 , and the score of 17 is removed from the set, calculate the new
mean and median of the group.
8 The ages of 50 people at a party are shown in the table below.
Age (years) 0–9 10–19 20–29 30–39 40–49 50–59 Over 60
Frequency 3 7 1 28 6 2 3
How many people are aged:
a 0 – 9 ? b 30 or older?
c in their twenties? d not in their fifties?
Extended-response question
Two groups of students have their pulse rates recorded as beats per minute. The results are
listed here:
Group A: 65, 70, 82, 81, 67, 74, □ , 81, 88, 84, 72, 65, 66, 81, 72, 68, 86, 86
Group B: 83, 88, 78, 60, 81, 89, 91, 76, 78, 72, 86, 80, 64, 77, 62, 74, 87, 78
a How many students are in group B?
b If the median pulse rate for group A is 76 , what number belongs in the □ ?
c What is the median pulse rate for group B?
d Which group has the largest range?
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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