QUANTITATIVE VARIABLE IS DISCRETE OR CONTINOUS

Types of quantitative variable :

(i)  Discrete variable

(ii)  Continuous variable

Discrete variable :

Discrete variable takes exact number values and is often a result of counting.

Examples :

The number of people in a household:

The variable could take the values 1, 2, 3,...

The score out of 30 for a test :

The variable could take the values 0, 1, 2, 3, ..., 30.

Continuous variable :

Continuous variable takes numerical values within a certain continuous range. It is usually a result of measuring.

Examples :

The weight of newborn babies :

The variable could take any positive value on the number line but is likely to be in the range 0.5 kg to 7 kg.

For each of the following possible investigations, classify the variable as categorical, quantitative discrete or quantitative continuous :

Problem 1 :

Problem 2 :

State whether these quantitative (or numerical) variables are discrete or continuous :

a) the time taken to run 1500 meters

It is continuous.

b) the maximum temperature reached on a March day

It is continuous.

c) the weight of cargo taken on a ship

It is continuous.

d) the time taken for a battery to run down

It is continuous.

e) the number of trips made by a taxi

It is discrete

f) the number of people in a theatre.

It is discrete

g) the number of minutes spent sending text messages per day

It is continuous.

Problem 3 :

For each of the following, state if the data would be discrete or continuous:

(a) The number of people in a room

(b) The mass of a book

(c) The number of pages in a book

(d) The length of a line

(e) The time taken to complete a puzzle

(f) The size of a shoe

(g) The number of glasses in a dishwasher

(h) The volume of water in a bottle

(i) The number of songs in an album

(j) The weight of an apple

(k) The number of people at a football match

Solution :

(a) The number of people in a room will be integers or whole numbers. Then it is discrete data.

(b) The mass of a book will be a number in decimal, then it is continuous data.

(c) The number of pages in a book must be an integer, then it is discreate data.

(d) The length of a line will be in decimal, then it is continuous data.

(e) The time taken to complete a puzzle will differ in minutes and seconds, then it is continuous data.

(f) The size of a shoe is discrete.

(g) The number of glasses in a dishwasher will be discrete.

(h) The volume of water in a bottle will be continuous.

(i) The number of songs in an album will be discrete.

(j) The weight of an apple will be continuous.

(k) The number of people at a football match will be discrete.

Problem 4 :

A teacher collects the ages of students in her school. Is that variable discrete or continuous?

Solution :

When a teacher collects the ages of students, it must be integer. Then it is discrete.

Problem 5 :

Steven keeps a record of the prices of all the cars he sold in one year. Is that variable discrete or continuous ?

Solution :

Price of cars will be continuous

Amount of money earned last week

Arm span

Birthdate

Concentration exercise (seconds)

Dominant hand reaction time

Favourite sport Height

Hours slept per night.

Language mostly spoken at home

Foot length

Opinions on environmental conservation

School post code State/Territory live in

Travel method to school

Travel time to school

Year level

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