Problems adapted from questions set for previous Mathematics exams.
A survey is carried out by asking people questions as they come out of a coffee bar.
A section of the questionnaire is shown below.
(a) Explain why this is a biased survey.
(b) State two criticisms of the questions or the options given for answers.
Jimmy is ordering the t-shirts for the community choir which has 240 members.
He asks a sample of 36 members what colour the t-shirts should be. Each members chooses one colour.
The table shows information about his results.
|Colour||Number of members|
(a) Work out how many of the 240 members you think will want black t-shirts.
(b) State any assumption you made and explain how this may affect your answer.
Donna is in a class of 25 students, 5 of whom have a pet dog.
There are 2200 students in the school.
(a) Use this information to estimate how many students in the school have pet dogs.
(b) Luka is at a different school.
She is in a class of 28 students, 7 of whom have pet dogs.
Luka and Donna have an idea. They think "In our two classes there are 53 students, 12 of whom have a pet dog. We can use this bigger sample to improve the estimate for Donna's school."
What assumption have they made?
(c) Use this idea to estimate how many students in Donna's school have pet dogs.
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