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6.1 Identifying data

4 Method of collection: Questionnaire.
5 Sample size: There are 380 adults in my village. 10% of 380 = 38, so 19 males and 19 females.
6 Accuracy of data: Heights measured to the nearest cm, masses to the nearest kg, hours of
exercise to the nearest half-hour.
ii She could also collect data on diet, age, blood pressure, cholesterol levels, family history of illness.
iii The adults in her village may not want to give sensitive information such as how much they weigh,
their blood pressure, cholesterol level or family history of illness.

) Exercise 6.1

1 Write a hypothesis for each of these investigations.
a Sasha wants to know whether more men than women watch sport on the TV.
b Anders wants to know if silver is the most popular colour of car that is sold.
c Oditi wants to know if girls are better than boys at estimating the masses of different objects.
d Alicia wants to know whether it is true that the more you revise the better your exam result will be.

2 There are 800 students in Dakarai’s school.
He wants to know whether boys or girls are better at maths. Work in pairs, or groups
a Write down examples for each of the six steps for Dakarai to follow. of three, to answer
b What other factors could Dakarai consider? questions 2 and 3.
c Write down some problems he might have in collecting his data.
3 Kiera is reading a book that has 120 pages.
She wants to know whether ‘e’ is the most commonly used letter in the book.
a Write down examples for each of the six steps for Kiera to follow.
b What other factors could Kiera consider?
c Write down some problems Kiera might have in collecting her data.

4 Razi is talking to Mia. He wants to know the favourite sport of the students in his school.
He uses all the students in his class as his sample. There are 15 boys and 3 girls in his class.
The favourite sport of the students in his class is cricket.
The favourite sport of the students in his class is cricket.
But you cannot assume cricket is the
The favourite sport favourite sport of the students in the
of the students in my whole school, as most of the students in
school must be cricket. your class are boys. The school has equal
numbers of boys and girls so you need to
sample equal numbers of boys and girls.

For each part of this question give a reason why the conclusion is not valid and suggest a better

sample that they could use.
a Hassan wants to know who are better at spelling in his school, the boys or the girls. He tests all the
students in his top-set maths class. There are 12 boys and 18 girls in his class. Hassan says: ‘The
boys had better scores than the girls, so the boys in the school are better at spelling than the girls.’
b Harsha lives in a village 25 km from her school. She catches a bus to school every morning. There
are 520 students in her school. Harsha wants to know the most popular method of travelling to
school. She asks the 24 students who live in her village. Harsha says: ‘Most of the students who I
asked travel to school by bus. So, the most popular method of travelling to school, used by all the
students in the school, is the bus.’
6 Planning and collecting data 57