IDENTIFYING VARIABLES

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Something that varies. Symbol to which numerals or values are attached.

Concept or its empirical measure that can take on multiple values.

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Concepts are mental images or perceptions.

Indicators : set of criteria reflective of the concept which can be then converted into variables.

Variables are measurable with varying degrees of accuracy.

A concept cannot be measured whereas a variable can be subjected to measurement.

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Concept Indicator Variable

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Concept Indicator Variable Decision level

Rich 1. Income 2. Assets

1. Income per year

2. Total value of : home (s), investment, car, boat

1. If > AED 100 000

2. If > AED 250 000

High academic achievement

1. Avg. marks in exams

2. Avg. marks in assig.

3. Aggregate marks

1. % of marks2. % of marks 3. % of marks

1. If > 75%2. If > 75%3. If > 80%

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A variable can be classified in a number of ways. The classification developed here results from looking at variables in three ways:

1.The Causal relationship 2.The design of the study3.The unit of measurement

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In studies attempting to investigate a causal relationship or association may involve four types of variables:

1. Independent Variable (IV) : this is a variable responsible for bringing changes in a phenomenon or a situation.

2. Dependent Variable (DV) : is the outcome of the changes brought by an independent variable.

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3. Extraneous Variable : other variables, not measured in a study, may increase or decrease the magnitude or strength of the relationship between IV & DV.

4. Intervening Variable : this is a variable links the IV & DV. This is a situation where the relationship between IV & DV cannot be established without the intervention of another variable.

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Extraneous Variables affecting the relationship

Income

Subject area Experience Environment

IVDV

Education

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IV

Transportations Extent of the use of transportations

Intervening Variables DV

Economic growth

Roads Cost

Technologies Facilities

Extraneous Variables

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Active variables : those variables can be manipulated, changed or controlled.

Example: teaching methods , experimental intervention, program, service etc.

Attribute variable : Those variables that cannot be changed or manipulated or controlled, and that reflect the characteristics of the study population.

Examples: age, gender, education, income etc.

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From the viewpoint of the unit of measurement, there are two ways of categorizing variables:

1.Whether the unit of measurement is categorical or continuous in nature

2.Whether is qualitative or quantitative in nature

Categorical variables are variables that can be divided into categories or arranged according to order. The variables are measured on nominal or ordinal measurement scales, and can be of three types:

1. Constant Variable : has only one category. Example: fire, water, tree, taxi etc.

2. Dichotomous Variable : has two categories. Example: yes/no, male/female, good/bad.

3. Polytomous Variable : has more than two categories. Example: Labor, Liberal, Democrat; student, faculty member, administrative staff. 13

These are variables measured either on an interval or a ratio scale , have continuity of measurement.

They can take on any value on the scale on which they are measured.

Example: age and income.

Age can be measured in years, months and days.

Similarly, income can be measured in dollars and cents.

Categorical variables Continuous Qualitative Quantitative

Constant

Dichotomous

Polytomous

-water

-tree

-taxi

-yes/no

-good/bad

-rich/poor

-day/night

-male/female

Attitudes -strongly favourable-favourable-uncertain -strongly unfavourable

Political parties-Labor -Liberal-Democrat

Age -old -young -child

Income ($)

Age (years)

Weight (kg)

Age -old-young-child

Income -high-middle -low

Gender -male -female

Age ……..(years/months

Income …..(per year)

Temperature ……..c or F

There are four types of measurement scale:

1.Nominal or classificatory scale

2.Ordinal or ranking scale 3.Interval scale 4.Ratio scale

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A nominal scale enables the classification of individuals, objects or responses based on a common or shared property or characteristic.

These people, objects or responses are divided into a number of subgroups in such a way that each member of the subgroup has a common characteristic.

Classification by means of a nominal scale ensures that individuals, objects or responses within the same subgroup have a common characteristic or property as the basis of classification.

The sequence in which subgroups are listed makes no difference as there is no relationship among subgroup.

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Measurement scale

Example Characteristics

Nominal / classificatory

-tree -house -taxiGender -male-female Political parties-Labor -Liberal-Democrat Age -old -young -child

Each subgroup has a characteristic which is common to all classified within that group

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An ordinal scale has all the properties of a nominal scale plus one of its own.

Besides categorizing individuals, objects, reposes or a property into subgroups on the basis of a common characteristic, it ranks the subgroups in a certain order.

They are arranged either in ascending or descending order according to the extent a subcategory reflects the magnitude of variation in the variable.

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Measurement scale

Example Characteristics

Ordinal /Ranking

Income -above average-average-below average

Attitudes -strongly favourable-favourable-uncertain -strongly unfavourable

It has characteristic of a nominal scale, e.g. individuals groups, characteristic classified under a subgroup have common characteristic

Plus Subgroups have relationship to one another. They are arranged in ascending or descending order

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An interval scale has all the characteristics of an ordinal scale; that is, individuals or responses belonging to a subcategory have a common characteristic and the subcategories are arranged in an ascending or descending order.

In addition, an interval scale uses a unit of measurement that enables the individuals or responses to be placed at equally spaced intervals in relation to the spread of the variable.

This scale has starting and terminating point that is divided into equally spaced units/intervals.

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Measurement scale

Example Characteristics

Interval

Temperature :Celcius : 0 cFahrenheit: 32 FAttitudinal scale : -10-20-21-30-31-4041-50 etc.

It has all the characteristics of an ordinal scale

Plus a unit of measurement with starting and terminating point.

Characteristics and examples of the scales

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A ratio scale has all the properties of nominal, ordinal and interval scales plus its own property: the zero point of a ratio scale is fixed, which means it has a fixed starting point.

Therefore, it is an absolute scale The difference between the intervals is always

measured from a zero point. This means the ratio scale can be used for

mathematical operations. The measurement of income, age, height and

weight are examples of this scale.

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A person who is 40 years of age is twice as old as a 20-year old.

A person earning AED 60,000.00 per year earns three times the salary of a person earning AED 20,000.00

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Measurement scale

Example Characteristics

Ratio

Height : cmIncome : $Age : year/monthWeight : kg

It has all the properties of an interval scale

Plus a fixed starting point (e.g. a zero point)

Characteristics and examples of the scales

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END Of CHAPTER 4

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