Page 109 - Mathematics Coursebook

10.2 The mean

4 Last season Rio’s football team scored 50 goals in 20 matches.
This season they scored 60 goals in 25 matches.
Work out the mean number of goals per match for each season.

5 Shona recorded the number of hours of sunshine for eight days.
Work out: a the mean b the mode c the median. 6 0 5 8 2 9 9 9
6 25 students in a class each estimated the size of an angle.
Their answers are recorded in this frequency table.

Estimate° 50° 55° 60° 65°
Frequency 6 10 7 2

a Find the mode.
b Work out the mean of all the estimates.
c How many estimates were below the mean?
d How many estimates were above the mean?
7 This table shows the numbers of cars owned by 20 different families living in one street.

Number of cars 0 1 2 3 4

Number of families 5 8 4 2 1

a Work out the modal number of cars.
b Work out the mean number of cars per family.

8 The mean age of five children in a family is 12 years.
Work out the total age of the children.
9 The mean mass of four women is 60 kg.
Another woman has a mass of 70 kg.
Work out the mean mass of the five women.
10 In a group of four children, their mean height is 1.40 m.
In another group of six children, their mean height is 1.60 m.
Work out the mean height of all ten children.

11 A student carries out a survey of favourite colours.
a Can she find the average colour? Give a reason for your answer.
b Can she find the range of colours?

12 Here is a set of numbers:
10, 10, 10, 10, 11, 12, 13, 15, 17
a Find (i) the mode, (ii) the median, (iii) the mean.
b There is a mistake in the set of numbers. The 17 should be 26.
Find the correct value for (i) the mode, (ii) the median, (iii) the mean.

108 10 Averages