Page 65 - Mathematics Coursebook

6.1 Planning to collect data

6.1 Planning to collect data

When you want to answer questions or solve problems that need information, you need to know where
to collect or $nd the data that you need. #ere are two types of data.

Primary data is information that you collect yourself. You can carry out a survey and ask people
questions, or you can carry out an experiment and write down your results.
Secondary data is data that someone else has already collected. You can look on the internet or in
books, newspapers and magazines to $nd this type of data.

Worked example 6.1

a If you were doing a survey, which units would you use to measure:
i the weight of 12-year-old children
ii the amount of time for which people are not at work due to illness?
b Where would you get data to help answer the following questions?
i How many students are there in your school?
ii Which ocean is the largest in the world?
c Would you collect primary data or secondary data to answer the following questions?
i What is the favourite colour of the students in your class?
ii What is the most popular make of car in your country?
d Mysha wants to know if the teachers in her school prefer to do a number puzzle or a crossword
puzzle. She only asks the maths teachers. Will the results of her survey give a fair result?

a i kg Weights of children and adults are usually measured in kilograms.
ii days Records usually show how many days people take off work due to illness.
b i School records You could ask the school secretary, head teacher or class teacher to check the
school records to find out how many students there are in your school.
ii Encyclopaedia You could look in an encyclopaedia, a fact book, a geography book or on the
internet to find the answer to this question.
c i Primary data You would need to ask the students in your class what their favourite colour
is to find the answer to the question.
ii Secondary data You wouldn’t be able to collect this information yourself. You would need
to find the information from somewhere else, such as government records,
survey results or car company records.

d No She needs to ask teachers of all subjects. Maths teachers are probably more
likely to do number puzzles than crossword puzzles since they like maths.

) Exercise 6.1

1 If you were doing a survey, which units shown on the right would you use to measure:
a the time it takes to for a person to run 100 m kilograms days
b the distance a person can cycle in 1 hour millilitres
c the length of time a person sleeps at night seconds millimetres
d the length of a person’s thumbnail? kilometres
hours metres

64 6 Planning and collecting data