year 8 maths

9G
Mean, median, mode and range
567
7 Bernadette writes down how many hours she works each day for one week.
Day Monday Tuesday Wednesday Thursday Friday
Number of hours 8 10 8 7 9
a What is the mean number of hours Bernadette worked each day?
b What is the median number of hours Bernadette worked each day?
c What is the mode number of hours Bernadette worked each day?
d If the number of hours worked on Tuesday changed to 20 (becoming an outlier), which
measure of centre would be changed?
PROBLEM-SOLVING AND REASONING
8, 9, 13, 14 8–10, 13, 14
10–16
8 The set 3, 7, 9, 10 has one extra number added to it, and this causes the mean to be doubled.
What is the number?
9 Alysha’s tennis coach records how many double faults Alysha has served per match over a number
of matches. Her coach presents the results in a table.
Number of double faults 0 1 2 3 4
Number of matches with this many double faults 2 3 1 4 2
a In how many matches does Alysha have no double faults?
b In how many matches does Alysha have three double faults?
c How many matches are included in the coach’s study?
d What is the total number of double faults scored over the study period?
e Calculate the mean of this set of data, correct to one decimal place.
f What is the range of the data?
10 A soccer goalkeeper recorded the number of saves he makes per game during a season. He presents
his records in a table.
Number of saves 0 1 2 3 4 5
Number of games 4 3 0 1 2 2
a How many games did he play that season?
b What is the mean number of saves this goalkeeper
made per game? Use the x button on your calculator
to check your answer.
c What is the most common number of saves that the
keeper had to make during a game?
11 Give an example of a set of data with:
a a mean of 10 and a range of 2
b a median of 10 and a range of 5
c a range of 100 and a mean of 50
d a mean of 6 , a median of 7 and a mode of 5
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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