CHAPTER NINE

Topic 9:

DATA COLLECTION AND PRESENTATION

Key words: data, chart, pie, quantitative, qualitative, discrete,

continuous, hypothesis

By the end of this topic, you should be able to:

a) understand the differences between types of data.

b) collect and represent simple data from local environment using

bar chart, pie chart and line graph.

Introduction

In this topic, you will learn different types of data, data collection,

presentation and analysis.

Sub-topic 9.1: Types of Data

Qualitative data is data that is not given numerically; e.g. favourite colour, place of birth, favourite food, and type of car.

Quantitative data is numerical. There are two types of quantitative data: discrete and continuous data. Discrete data can only take specific numeric values e. g. shoe size, number of brothers, number of cars in a car park. Continuous data can take any numerical value e.g. height, mass, length.

Activity 9.1: Identifying types of data

In your groups identify which of the following terms best describes

each of the information listed (i) to (vii)?

Give reasons for your response.

• Qualitative data

• Continuous Quantitative Data

• Discrete Quantitative Data

i) Age

ii) Birth place

iii) Height

iv) World Ranking

v) Aces

vi) First serve School

vii) School life

In your groups identify more examples.

Exercise

1. Mr Okot starts to make a database for his lesson.

a) What is missing from Mr Okot’s database?

b) Which columns in the database contain quantitative data?

c) Which columns in the database contain qualitative data?

d) Write down what Mr Okot would put in his database if you joined his class.

2. Which of the following would give:

(i) Mass (ii) Number of cars

(iii) Favourite football team

(v) Price of chocolate bars

(iv) Colour of car

(vi) Amount of pocket money

(vii) Distance from home to school (viii) Number of pets

(ix) Number of sweets in a jar

(x) Mass of crisps in a packet.

3. The table below shows a database that has no entries.

a) Collect data from 10 people to complete the data base.

b) State whether each column contains:

i) qualitative data.

ii) continuous quantitative data.

iii) or discrete quantitative data.

c) Answer the following questions:

i) What is the most popular TV show?

ii) Who is the oldest?

iii) What is the favourite pop group for the youngest person?

d) Write 3 more questions you could answer using your database and write the answers to them.

Sub-topic 9.2: Collecting Data

In this section, you will see how data is collected, organized and interpreted, using a tally chart and then displayed using:

i) Pictograms

ii) Bar charts

iii)Pie charts

Note:

A hypothesis is an idea that you want to investigate to see if it is true or false. For example, you might think that most people in your school get there by bus. You could investigate this using a survey. A tally chart can be used to record your data.

Activity 9.2: Collecting data

In groups identify the means of transport each learner use to come to school. As a class identify how many of you use the same means of transport.

i) Which means of transport is used by the majority?

ii) Which one is the least used means of transport?

Example

The learners in a class were asked how they got to school.

Illustrate this data using:

a) a pictogram

b) a bar chart

c) a pie chart

What are the main conclusions that can be deduced from the data?

Solution

(a) If (stick man) is taken to represent 2 people, then the pictogram looks like:

i) Walk (4 and a half stick men)

ii) Bike (1 and a half stick men)

iii) Car (3 stick men)

iv) Bus (6 stick men)

(b) A bar chart for the data is illustrated below:

(c) To illustrate the data with a pie chart, you need to find out what angle is equivalent to one pupil. Since there are 360° in a circle and 30 pupils, then angle per pupil is 360 ÷ 30 = 12°.

To find the angle for walk, when there are 9 pupils, it is simply:

9 x 12 = 108° 

The complete calculations are shown below:

The corresponding pie chart is shown below:

From the data we can see that:

• the most common way of getting to school is by bus. (This is called the modal class or the mode.)

• the least popular way of getting to school is by bike.

Exercise

1. The children in a class were asked to state their favourite crisps.

The results are given in the tally chart below:

(a) Copy and complete the table by filling the frequencies.

(b) Represent the data on a bar chart.

(c) Draw a pictogram for this data.

(d) Copy and complete the following table and draw a pie chart.