Delving into Data Exemplar Questions and Answers. Year 10

Jack wants to pick a sample of 5 students from his
class to complete a survey. Which of these methods
will produce a random sample?
Picking the first five names he thinks of
Putting all the names in a hat and picking out five
Picking his five closest friends in the class
©White Rose Maths

3.

4.

Rosie wants to find out if people in her town are
happy with the library service.
She asks all of the people who live on her street
their opinions.
Explain why Rosie’s survey is not reliable
Suggest a way to improve Rosie’s survey
©White Rose Maths

5.

Rosie wants to find out if people in her town are
happy with the library service.
She asks all of the people who live on her street
their opinions.
Explain why Rosie’s survey is not reliable
e.g. the sample size is too small and
may not best represent the town
Suggest a way to improve Rosie’s survey
e.g. Conduct a random sample
©White Rose Maths

6.

There are about 80 000 trees in a forest.
A researcher wants to test 1% of the trees for a disease.
Compare these methods of choosing the sample.
Number all the trees and pick 800 numbers at random
Picking the first 800 at the entrance to the forest
Split the forest into 20 regions and pick 40 trees from each region
©White Rose Maths

7.

8.

Alex surveys 5% of the students at her school about a proposed
change to the school uniform.
She talks to 25 students in Year 10 and 15 students in Year 11
What is meant by the population in this case?
What is the size of the population?
Is Alex’s sample likely to be representative? Why or why not?
©White Rose Maths

9.

Alex surveys 5% of the students at her school about a proposed
change to the school uniform.
She talks to 25 students in Year 10 and 15 students in Year 11
What is meant by the population in this case?
All the students in the school
What is the size of the population?
800
Is Alex’s sample likely to be representative? Why or why not?
e.g. She has not included students from Year 7-9
©White Rose Maths

10.

11.

The table shows the number of
students in each year group in a
school.
Brett is conducting a survey and
decides to interview 10 students
from each year group.
Criticise Brett’s sampling method
and suggest an improvement.
Year
7
8
9
10
11
No. of
students
150
180
170
110
90
e.g. 10 students from Year 11 ≈ 11% of Year 11 students
whereas 10 students from Year 11 ≈ 5.5% of year 8 students
He should interview the same proportion of each year group
©White Rose Maths

12.

There are three age groups in a running club.
The table shows the number of people in each group.
Age group
No of members
12 - 14
156
15 - 17
336
18+
108
Dexter wants to survey a sample of the members.
He wants to survey 50 people altogether.
Work out the number of people he should ask from
each age group.
©White Rose Maths

13.

14.

House
No of students
Merlin
92
Potter
165
Gandalf
83
Glinda
217
The table shows the number of students in each of the
four houses of a school.
In a stratified sample, 7 students are selected from
Gandalf house.
How many students should be selected from each of
the other houses?
©White Rose Maths

15.

House
No of students
Sample
Merlin
92
8
Potter
165
14
Gandalf
83
7
Glinda
217
18
The table shows the number of students in each of the
four houses of a school.
In a stratified sample, 7 students are selected from
Gandalf house.
How many students should be selected from each of
the other houses?
7
83
=
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