Page 175 - Math Smart - 7

Collecting and recording data

We can use a data collection sheet or a questionnaire to help us collect
information about a product or an event.

Data collection sheet Questionnaire
Tally marks are often used to record numerical A questionnaire is a set of questions that allows a
information in a data collection sheet. Tally marks researcher to ask different people the same set of
are used to keep count by drawing marks. Every fifth questions. It can include closed and open-ended
mark is drawn across the previous four marks. questions.
Closed questions provide a list of answers to choose
from so that it is easy to organise data.
Open-ended questions have no suggested answers
Date: 1 |uly 2019 Day: Monday
so it can be difficult to organise data as there may be
Start time: 09:15 End time: 11:30
Total survey time: 1 hr 15 mins diverse opinions.
Location: Intersection of 1" Avenue and Main Street
Weather: Clear skies Surveyor: liana
Decide what you want to find out from the
masses. Ask a question.
Vehicle type Tally Total
Car ilHJfH JWifH III 23
V Decide what data you need to collect. There
Motorbike iittijtt nil 14
should always be a reason for collecting this data.
Bus 111 3
Truck mm 13 Design your questionnaire.
III
Bicycle mm iwt iwtiwt i 31
Conduct a survey using your questionnaire to
4
Other 0
collect and record your data.
Total 84
Organise your data in a table, graph or chart.

Frequency tables

Ungrouped data Grouped data
When data values are spread out, we bundle the
Ungrouped data is discrete data that is not
organised into groups. In an ungrouped data data into classes in a grouped data frequency table.
frequency table, data can be presented in a list. The difference between the lowest value and the
highest values in each class is called the class interval.
The class intervals must not overlap. Each data value
Age Tally Frequency
can only be in one class interval.
13 Nil 5
14 III 3 Age range Tally Frequency
15 nil 4 0-9 III 3
16 nil 4
10-19 ■m II 7
17 II 2 20-29 4Hh4ttt 1 11
18 II 2 30-39 m-m 1 11
Total 20
40-49 nil 4
50-59 nil 4
Total 40
■ iirsfc

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