Page 111 - MAT KS3 Y8 Cambridge CheckPoint

End-of-unit review

End-of-unit review

1 The table shows the lengths of the passwords used by 30 people on a website.

Length (characters) 8 9 10 11 12 13
Number of people 11 10 4 0 3 2
Find:
a the modal password length
b the median password length
c the mean d the range.
2 In some countries trousers are sold by waist size, in centimetres.
The table shows the sizes of 40 pairs of trousers sold in a shop on one day.

Waist size (cm) 80 85 90 95 100 105 110
Number sold 2 3 8 8 14 1 4
a Find: i the median size ii the mode iii the mean iv the range.
b Which average would be most useful for the shop manager? Why?
3 The table shows the numbers of words in 50 sentences in a magazine.

Number of words 1–5 6–10 11–15 16–20 21–25 26–30 31–35
Frequency 2 5 10 10 14 6 3

a Write down the modal class.
b Find the mean number of words in a sentence.
c What can you say about the median?

4 The table shows the results of a survey of the waiting time for 80 people at an airport
passport control.

Waiting time (minutes) 10– 20– 30– 40– 50–60
Frequency 8 30 25 10 7
a Find the modal class. b Estimate the median waiting time.
c Estimate the mean. d Estimate the range.

5 Students were asked to name the capital cities of 12 countries. The table shows their results.

Correct answers 6 7 8 9 10 11 12
Number of Boys 1 0 5 8 6 13 2
students Girls 0 4 0 10 12 5 1

a How many boys and girls took part?
b Use averages to decide whether boys or girls did better.
6 This table shows the number of words in 40 sentences in a newspaper.

Number of words 1–5 6–10 11–15 16–20 21–25
Frequency 2 7 16 10 5

Compare the sentence lengths in the newspaper with the magazine in question 3.
Find any useful statistics you need.

10 Processing and presenting data 109