objectives n variables

7/28/2019 Objectives n Variables

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Objectives andVariables

Ajeya Jha


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Objectives of discussion

To comprehend the nature of objectives To recognize how variables are related to

concept and indicators

To understand different types of variables

To understand different scales of

measurement

To learn how various statistical techniques

are related to nature of variable and scales ofmeasurement.


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Formulation of Objectives

Are goals to attain your study.

Are derived from the problem

statement Important to word them clearly and

specifically.

Are listed in two headings Main Objectives

Sub-objectives


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Main objective is an overall statement

of the thrust of study.

Statement of the main association/relationship to be discovered or

established.

Sub-objectives contain one aspect of

the study


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Wordings of your objectives determine

the type of research design you

undertake.


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CHARACTERISTICS OF YOUR

OBJECTIVES

Objectives should be

Clear

Complete

Specific

Specify the variables

Identify the direction of relationship

Measurable


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Variables

An image, perception or concept that is

capable of taking on different values is

called a variable.

Variables, indicators and concepts: Are

they same?


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Concepts and Variables

Concepts are mental images or

perceptions. E.g. strength, effectiveness

Are subjective

Not measurable

It is important that concepts are

converted to variables.


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Indicators and Variables

Indicators are a set of criteria reflective

of the concept.

Indicators can be converted to

variables


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Types of Variables

As per causal model

Independent Variables

Dependent Variables

Intervening variables

Extraneous variables

Extraneous variables are other

variables affecting DV

Intervening variables intervene in the

relationship between IV and DV.


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INDEPENDENT VARIABLESIN FACTORIAL DESIGNS


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Kinds of Variables

Independent Variable something

that is changed by the scientist

What is tested What is manipulated


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Kinds of Variables

Dependent Variable something

that might be affected by the

change in the independent variable What is observed

What is measured

The data collected during theinvestigation


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Students of different ages weregiven the same jigsaw puzzle

to put together. They were

timed to see how long it took to

finish the puzzle.


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Identify the variables in this

investigation.


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What was the independent

variable?

Ages of the students

Different ages were tested by

the scientist


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What was the dependent

variable?

The time it to put the puzzle

together

The time was observed and

measured by the scientist


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What was a controlled variable?

Same puzzle

All of the participants were

tested with the same puzzle.It would not have been a fair

test if some had an easy 30

piece puzzle and some had aharder 500 piece puzzle.


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An investigation was done with anelectromagnetic system made from a

battery and wire wrapped around a

nail. Different sizes of nails wereused. The number of paper clips the

electromagnet could pick up was

measured.


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What are the variables in this

investigation?


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Independent variable:

Sizes of nails

These were changed by the

scientist


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Dependent variable:

Number of paper clips

picked up

The number of paper clips

observed and counted

(measured)


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Controlled variables:

Battery, wire, type of nail None of these items were changed


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The higher the temperature

of water, the faster an eggwill boil.


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Independent variable

temperature of water

Dependent variable time to cookan egg

Controlled variable type of egg


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The temperature of water

was measured at different

depths of a pond.


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Independent variable depth of

the water

Dependent variable temperature Controlled variable

thermometer


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The greater the amount of soap in

a soap and water mixture, the

bigger a soap bubble can beblown.

Design an investigation to test thishypothesis.

Identify the variables

What exactly will be changed? Howwill it be changed?

What exactly will be measured?How will it be measured?


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The farther a ball drops, the

higher it will bounce

Design an investigation to test

this hypothesis.

Identify the variablesWhat exactly will be changed?

How will it be changed?

What exactly will be measured?How will it be measured?


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What Makes for Good Variables? Answer

Is the independent variablemeasurable?

Yes / No

Can you change the independentvariable during the experiment?

Yes / No

Have you identified all relevantdependent variables, and are they all

caused by and dependent on theindependent variable?

Yes / No

Are all dependent variable(s)measurable?

Yes / No

Have you identified all relevantcontrolled variables?

Yes / No

Can all controlled variables be held at a

steady value during the experiment?Yes / No


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As per study design

Active variables

Attribute variables


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Unit of Measurements

Quantitative variables

Qualitative variables

OR Continuous variables

Discrete Variables


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Active and Attribute variables

Active Variables that can be

manipulated

E.g. teaching method, communication

Attribute that can not be manipulated

Age, gender, level of education


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Quantitative Vs Qualitative

Quantitative: Mathematical value

Qualitative: No mathematical value


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Continuous Vs Categorical

Continuous: Have continuity in their

measurement.

Categorical: Not continuous I their

measurement.

Constant

Dichotomous

Polytomous


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Scales of Measurement

Nominal scale

Ordinal scale

Interval scale

Ratio scale


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Nominal Scale: When data are labels or

names used to identify the attribute of

an element, the nominal scale is used.

Ordinal Scale: In addition to nominal

level data capacities, ordinal scale can

be used to rank or order objects.


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Interval Scale: In interval level measurement, the

difference between two consecutive numbers is

meaningful.

Ratio Scale: Ratio level measurements possess all theproperties of interval data with meaningful ratio of two

values.

In terms of measurement capacity, nominal, ordinal,interval, and ratio level data are placed in ascending

order.


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A comparison between the four levels of data

measurement in terms of usage potential

Independent variables


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Independent variables

Nominal Ordinal Interval

Nominal

Crosstabs/Chi-square

Chi-square

Discrimin

ant/Logistic/Regression

Ordinal

Nonparametrictests/ordinal

regression

Non-parametriccorelatio

ns

OrdinalRegressio

n

Interval

T-test,Anova

Correlation/Regression

D

E

PE

N

D

E

N

T

V

A

R


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THANKS!

Any questionsPlease?

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