module 2 (aagal nu adhuru) (tbm)

7/29/2019 Module 2 (Aagal Nu Adhuru) (TBM)

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Module-2 Basic ResearchMethods

Business Research- I


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Chapter Tour

Secondary Data Analysis with example (Self

Study)

Survey Research - Errors and Methods of

Communication

Observational Research- Nature and Types

Experimental Research- Issues and types of

Designs


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Topics Covered

Observation Methods- Nature and Types

Experimental Research- Issues and Types of

Designs


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OBSERVATIONALRESEARCH


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OBSERVATION RESEARCH

Observation becomes a tool for scientific inquirywhen it-

Serves a formulated research purpose.

Is planned systematically.

Is recorded systematically and related to generalpropositions rather than being presented asreflecting a set of interesting curiosities.

Is subjected to checks or controls on validity and

reliability.

Scientific observation is the systematic process ofrecording the behavioral patterns of people, objects,

and occurrences as they are witnessed.


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What can be observed?

Phenomenon Example

1) Human Behavior Work patterns or television viewing

2) Verbal Behavior Office conversations, statements

made by airline travelers waiting in

line

3) Expressive behavior Tone of the voice or facialexpressions, other forms of body

language

4) Spatial relations Physical distance between workers

or traffic patterns

5) Temporal patterns Amount of time spent shopping or

time required to perform a work

task

6) Physical objects Finished goods inventory, how

much paper office workersrecycle?


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The Nature Of Observation Studies

Human observers are commonly used when thesituation or behavior to be recorded is not easily

predictable in advance of the research.

Mechanical observation can be very accurate when

the situation or behavior to be recorded is routine,

repetitive, or programmatic.

Visible observation is a situation in which the

observers presence is known to the subject.

Hidden observation is a situation in which the subject

is unaware that observation is taking place.


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Observation of Human Behavior Surveys emphasize verbal responses, while

observation studies emphasize and allow for thesystematic recording of nonverbal behavior.

Behavior scientists have recognized that nonverbalbehavior can be a communication process by whichmeanings are exchanged between individuals.

Nonverbal Communication Symbols: head nods,smiles, raised eyebrows, and other facial

expressions or body movements. Observation of nonverbal communication has

considerable promise for the business researcher.

Of course, verbal behavior is not ignored, and in

certain cases verbal responses are very important in


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Supplementary Evidence The results of observation studies may amplify the

results of other forms of research by providing

complementary evidence concerning individuals

true feelings. Role-playing sessions and focus group interviews

are often conducted behind one-way mirrors, so that

researchers can observe as well as listen to what is

occurring. This allows for the interpretation of such nonverbal

behavior as facial expressions or head nods to

supplement information from interviews.


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DIRECT OBSERVATION

Researcher using the direct observation method

compile data by recording events as they occur.

Direct observation is often used to help keep the

observations consistent and to ensure that all relevant

information is recorded.

The recording of the observation is instantaneous.

It is the straightforward attempt to observe and record

what naturally occurs; the investigator does not create

an artificial situation.


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Errors associated with direct observation

Observer bias: A distortion of measurement resulting

from the cognitive behavior or actions of the

witnessing observer.

Interpretation of observation data is another major

source of potential error.

Response Latency: it is a measure of strength of the

preference between alternatives. It is hypothesized

that the longer a decision maker takes to make a

choice between two alternatives, the closer the two

alternatives are in terms of preference.


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CONTRIVED OBSERVATION

Observing subjects in an artificial environment inorder to test the hypothesis is called contrived

observation.

If situations werent contrived, the research timespent waiting and observing situations would

expand considerably.

Mystery Shopper: the term is used by a number of

retailers to describe this type of research, in which

an observer posing as a shopper comes into a store

and pretends to be interested in a particular product

or service. After leaving the store, the unknown


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OBSERVING SOCIAL SETTINGS

In many situations the purpose of observation is tosummarize, systematize, and simplify the activities,

meaning, and relationships in a social settings.

Often, unstructured methods provide the observer with

the greatest flexibility.

Elements of interest in most social settings:

1) The participants

2) The settings3) The purpose

4) The social behavior

5) Frequency and duration


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PARTICIPANT OBSERVATION

It refers to an observation situation in which anobserver gains firsthand knowledge by being in or

around the social settings that is being investigated.

The participant observer must develop a system for

recoeding his or her observations.

The observer takes mental notes and jots down field

notes where possible.

More detailed field notes are recorded to summarizeand synthesize the events and activities of the day.


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Ethical Issues in Human Observation

Hidden observation: Raise the issue of the subjectsright to privacy.

Contrived observation: raise the possibility of

deception of subjects.

Some people might see contrived observation asentrapment.

To entrap means to deceive or trick into difficulty,

which clearly is an abusive action. The problem is

one of balancing values.


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OBSERVATION OF PHYSICAL OBJECTS

Physical-trace evidence is a visible mark of somepast event or occurrence.

It provides comparison between the results of

surveys and observation.

The results are so specific that they can show what

brand of soft drink was consumed with a certain

meal.

An observer can record physical-trace data todiscover things that a respondent could not recall

accurately.

The problem of untruthfulness or some other form of

response bias is avoided.


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CONTENT ANALYSIS

Content Analysis obtains data by observing andanalyzing the content or message of advertisements,

union contracts, reports, letters, and the like.

It involves systematic analysis as well as

observation, to identify the specific information

content and characteristics of the messages.

This technique measures the extent of emphasis, or

omission of emphasis, on any analytical category.

Study of the content of communications is more

sophisticated than simply counting the items; it

requires a system of analysis to secure relevant

data.


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MECHANICAL OBSERVATION

In many situations the primary means of observationis mechanical rather than human.

In mechanical observation, videotape, cameras, traffic

counters, and other machines record behavior.

Some unusual observation studies have used amotion picture camera and time-lapse photography.

Mechanical observational techniques may be used in

research to help design store layouts and to resolve

problems in moving people or objects through variousspaces over time.


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The various mechanical observational

techniques are

1) Television Monitoring

2) Monitoring Web Site Traffic

3) Optical Scanners and Bar Codes

4) Measuring Physiological Reactions


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1) Television Monitoring

A.C. Nielsens System is the best-known businessresearch project involving mechanical observation

and computerized data collection for estimating

national television audiences.

Nielsen uses a consumer panel and a sophisticatedmonitoring device called a PeopleMeter to obtain

ratings for television programs in 18 countries.

Electronic boxes are hooked up to television sets to

capture important information on program choices,the length of viewing time, and the identity of the

viewer.

Nielsen is working on more sophisticated digital cable

technology that uses a set-top box decoding system.


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2) Monitoring Web Site Traffic

Hit: it occurs when a user clicks on a single page of a

website

Page view: it indicates how many users visit each

individual page on the website, and they may also be used

to track the path or sequence of pages that each visitor

follows.

Jupiter Media Metrix and Nielsen//Net Ratings are

companies that specialize in monitoring internet activity.

The typical internet monitoring company installs a special

tracking program on the personal computers of a sample ofinternet users who agree to participate in the research

effort.

For Ex: Nielsen//Net Ratings has its software installed on

225,000 computers, in homes and workplaces, in 26


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3) Optical Scanners and Bar Codes

Mechanical observation can also be based on opticalcharacter recognition or bar code systems such as

the Universal Product Code (UPC).

Systems based on the UPC bar-code technology

have been implemented in factories, warehouses,and transportation companies to research inventory

levels, shipments, and the like.

Optical scanners in supermarkets provide a wealth

of product and brand sales information.


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EYE TRACKING

MONITORS

Pupilometers

Psychogalvanometers

Voice Pitch Analyzers

The gaze movements of theeye are measured with aneye camera or eye viewmonitor.

It measures unconscious eyemovements.

These devices tracktelevision viewers eyemovements and focal points

through an invisible infraredlight beam that locks ontosubjects eyes.

Modern eye-tracking systems

do not require keeping a


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Eye Tracking Monitors

PUPILOMETERS

Psychogalvanometers


A Pupilometer observes and

record changes in the

diameter of the pupils of the

eyes.

Subjects are instructed to

look at a screen on which an

advertisements is projected.

This research is based on theassumption that increased

pupil size reflects positive

attitudes toward and interest

in the stimulus.


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Pupilometers

PSYCHOGALVANOMETE

RS


It measures Galvanic SkinResponse (GSR), or

involuntary changes in the

electric resistance of the

skin. Use of this device is

based on the assumption

that physiological

changes, such asincreased perspiration,

accompany emotional

reactions to

advertisements,


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Pupilometers

Psychogalvanometers

VOICE PITCH

ANALYZERS

It measures emotionalreactions as reflected in

physiological changes in a

persons voice.

Abnormal frequencies in thevoice, cause by changes in

the autonomic nervous

system, are measured with

sophisticated audio-adaptedcomputer equipment.

This technique does not

require subjects to be

surrounded by mazes of


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EXPERIMENTAL RESEARCH


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Independent Variables (IV)

In an experiment, the independent variable is the

variable that is varied or manipulated by theresearcher.

It is the variable that is controlled and manipulated

by the experimenter.

An independent variable is measured, manipulated,

or selected by the experimenter to determine its

relationship to an observed phenomenon.

For example, an experiment to test the effects of a

certain fertilizer, upon plant growth, could measure

height, number of fruits and the average weight of

the fruit produced. All of these are valid analyzable

factors, arising from the manipulation of one

independent variable, the amount of fertilizer.


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Dependent Variables (DV)

In an experiment, a dependent variable is the factorwhich is observed and measured to determine the

effect of the independent variable, that is, that factor

that appears, disappears, or varies as the

experimenter introduces, removes, or varies the

independent variable.

The DV is the criterion or standard by which the

results are judged. The factor manipulated by the researcher, and it

produces one or more results, known as dependent

variables.

It is the variable that is measured by the


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Independent Variables (IV) Dependent Variables (DV)

1) It is the variable that is varied

or manipulated by theresearcher.

1) It is the response that is

measured.

2) It is the presumed cause. 2) It is the presumed effect.

3) It is the antecedent. 3) It is the consequent.

4) It is the variable that is

controlled and manipulated by

the experimenter.

4) It is not manipulated, instead

the dependent variable is

observed or measured for

variation as a presumed resultof the variation in the

dependent variable. Dependent

variables can be influence by

controlled variables.


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Extraneous Variables

This type of variable is one that may have an impact on the

relationship between the independent and dependentvariables. The two types of extraneous variables.

Participant Variables: These extraneous variables arerelated to individual characteristics of each participant that

may impact how he or she responds. These factors can

include background differences, mood, anxiety, intelligence,

awareness and other characteristics that are unique to

each person.

Situational Variables: These extraneous variables are

related to things in the environment that may impact howeach participant responds. For example, if a participant is

taking a test in a chilly room, the temperature would be

considered an extraneous variable. Some participants may

not be affected by the cold, but others might be distracted

or annoyed by the temperature of the room.


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EXPERIMENTAL RESEARCH

A research method in which conditions are controlledso that one or more variables can be manipulated in

order to test a hypothesis.

Experimentation is a research method that allows

evaluation of causal relationships among variables.

Purpose: To allow the researcher to control the

research situation so that causal relationships

among variables may be evaluated. The experimenter therefore manipulates a single

variable in an investigation and holds constant all

other relevant, extraneous variables.


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Experiments differ from other research methods in

terms of degree of control over the research

situation. In typical experiment one variable (Independent

Variable) is manipulated and its effect on another

variable (Dependent Variable) is measured, while all

other variables that may confound such arelationship are eliminated or controlled.

The experimenter either creates an artificial situation

or deliberately manipulates a situation.

Once the experimenter manipulates the independentvariable, changes in the dependent variable are

measured.

The essence of a behavioral experiment is to do

something to an individual and observe his or her


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Basic Issues in Experimental Design

Decisions must be made about severalbasic elements of an experiments:

1) Manipulation of the IV.

2) Selection and Measurement of the DV.

3) Selection and Assignment of test units.

4) Control over extraneous variables.


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1) Manipulation of the Independent Variable

The experimenter has some degree of control overthe IV.

Experimental Treatments are the manipulations ofthe IV being investigated.

In business research, IV is often a categorical or

classificatory variable, representing some classifiable

or qualitative aspects of management strategy.

IV can be Continuous Variable. A continuous variableis one for which, within the limits the variable ranges,

any value is possible.

The researcher must select the appropriate levels of

IV for experimental treatments.


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Experimental Groups: The group of subjects

exposed to an experiment treatment.

Control Groups: A group of subjects who areexposed to the control condition in an experiment

that is, they are subjects not exposed to the

experimental treatment.

Several Experimental Treatment Levels: If theresearcher wished to understand the functional

nature of the relationship between several treatment

levels, additional experimental groups might be

studied. This type of design would allow the experiment to

get a better idea of the impact.

More than one Independent Variable: It is possible

to assess the effects of more than one independent


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2) Selection and Measurement of Dependent

Variable

The dependent variable is so named because its valueis expected to be dependent on the experimentersmanipulation of the independent variable.

It is assumed that changes in the dependent variable

are a consequence of changes in the independentvariable.

The experimenters choice of a dependent variabledetermines what type of answer is given to the

research question. In some experiments the amount of time required for

the effects to become evident should be considered inchoosing a dependent variable.

Productivity may be measured several months after


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3) Selection and Assignment of Test Units

Test Units: Test Units are the subjects or entities whoseresponses to the experimental treatments are

measured or observed.

People and departments within organizations are the

most common test units in most business behavioralexperiments.

Sample Selection Error and Random Sampling Error

Sample Selection Error is an administrative procedural

error caused by improper selection of a sample, thus

introducing bias.

Random Sampling error is a statistical fluctuation that


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Randomization

It is a procedure in which the assignment of subjects

and treatments of groups is based on chance.

Random assignment of subjects and treatments is

one device for equally distributing, or scattering, the

effects of extraneous variables.

Randomization assures the researcher thatrepetitions of an experiment- under the same

conditions- will show the true effects, if they exist.

Random assignment of subjects allows the

researcher to assume that the groups are identicalwith respect to all variables except for the



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Matching

It is a procedure for the assignment of subjects to

groups; it ensures each group of respondents ismatched on the basis of pertinent characteristics.

If the experimenter believes that certain extraneous

variables may effect the dependent variable, he or

she can make sure that the subjects in each groupare matched on these characteristics.

Repeated Measures

It is the experimental technique in which the same

subjects are exposed to all experimental treatments

in order to eliminate any problems due to subject

differences.


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4) Control Over Extraneous Variables

Establishing Control The major difference between experimental research

and other research is the experimenters ability to hold

certain conditions constant and to manipulate the

treatment.

When extraneous variables cannot be eliminated,

experimenters may strive for constancy of conditions,

A procedure in which subjects in experimental groups

are exposed to situations identical except for differing

conditions of the independent variable.

If the experimenter method requires that the same

subjects to be exposed to two or more experimental

treatments, there is a ossibilit of order of


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Order of presentation bias is an error in an

experiment caused by subjects accumulating

experience in the course of responding to multiple

experimental treatments.

Counterbalancing is a technique to reduce error

caused by order of presentation by varying the order

of experimental treatments for different groups.

Blinding is a technique used to control subjects

knowledge of whether o r not they have been

given a particular experimental treatment.

Double-blind Design is a technique in which neitherthe subjects nor the experimenter knows which are

the experimental and which are the controlled

conditions.


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Problems Controlling Extraneous Variables

In business experiments it is not always possible to

control everything that should be controlled in orderto have the perfect experiment.

Business researchers may also be constrained by

managements greater concern with efficiency than

with research.Constant Experimental Error

Constant error is an error that occurs in the same

experimental condition every time the basic

experiment is repeated.

It occurs when the extraneous variables or the

conditions of administering the experiment are

allowed to have an influence on the dependent

variables every time the experiment is repeated.


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Demand Characteristics

It refers to experimental design procedures thatunintentionally hint to subjects about theexperimenters hypothesis; situational aspects of anexperiment that demand that the participant respondin a particular way.

If participant recognize the experimenters

expectation or demand, they are likely to act in amanner consistent with the experimental treatment.

If an experimenters presence, actions, or commentsinfluence subjects behavior or influence subjects to

slant their answers to cooperate with anexperimenter, the experiment has experimentersbias.

Guinea Pig Effect is an effect on the results of an

experiment caused by subjects changing theirnormal behavior or attitudes in order to coo erate


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Hawthorne Effect is an unintended effect on the

results of a research experiment caused by the

subjects knowing that they are participants. To reduce demand characteristics, steps are taken to

make it difficult for subjects to know what the

researcher is trying to find out in the experiment.

Experimenters are trained and experimentalsituations are designed to reduce cues that might

serve as demand characteristics.


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Ethical Issues in Experimentation

Experimental research must address privacy,confidentiality, deception, accuracy of reporting, and

other ethical issues.

The question of subjects right to be informed,

however, tends to be very prominent inexperimentation.

Debriefing is the process of providing subjects with all

the pertinent facts about the nature and purpose of

the experiment after the experiment has beencompleted.

Another issue that may arise in business experiments

is the subjects right to safety from physical and

mental harm.


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Fundamental Experimentation Designs

1) Basic Versus Factorial Experimental Designs

2) Laboratory and Field Experiments.


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1) Basic versus Factorial Experimental Designs

In basic experimental designsa single independent

variable is manipulated to observe its effect on a

single dependent variable.

Factorial experimental designs allow for

investigation of the interaction of two or more

independent variables.

2) Laboratory and Field Experiments

It is an experiment conducted in a laboratory or

artificial setting to obtain almost complete control

over the research setting. Tachistoscope is a device that controls the amount

of time a subject is exposed to a visual image.

Field Experiment is conducted in a natural settings,

often for a long period of time


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Tachistoscope


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Issues in Experimental Validity

1) Internal Validity

It indicates whether the independent variable was thesole cause of the change in the dependent variable.

If the observed results are influenced by theconfounding effects of extraneous factors, theresearcher has problems making valid conclusions

about the relationship between experimental treatmentand the dependent variable.

The six major types of extraneous variables that mayjeopardize internal validity:

1) History

2) Maturation3) Testing

4) Instrumentation

5) Selection

6) Mortality


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2) External Validity

It indicates the extent to which the results of theexperiment are applicable in the real world.

It is to check the ability of the experiment togeneralize the results to the external environment.

The experimental situation may be artificial and itmay not represent the true setting and conditions in

which the investigated behavior takes place.

If the study lacks external validity, it will be difficult torepeat the experiment using different subjects,settings, or time intervals.

Two major issues are:1) Student Surrogates

2) Trade-offs

Classification of Experimental Designs


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Classification of Experimental Designs

1) Basic Experimental Design

a) Symbolism for diagramming Experimental Designsb) Pretest-posttest control Group Design

c) Posttest-only Control Group Design

d) Solomon Four-Group Design

e) Compromise Experimental Designs

f) Time-series Experimental Designs

2) Complex Experimental Design

a) Completely Randomized Designb) Randomized Block Design

c) Factorial Designs

d) Latin Square Design


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1) Basic Experimental Designs

It is an experimental design in which a single

independent variable is manipulated in order toobserve its effect on a single dependent variable.

1. Symbolism for diagramming experimental designs

2.Pretest-posttest control Group Design

3. Posttest-only Control Group Design

4. Solomon Four-Group Design

5. Compromise Experimental Designs

6. Time-series Experimental Designs


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1) Symbolism for diagramming experimental designs

The classic work of Campbell and Stanley has aided

many students in understanding the subjects ofexperimental designs.

The following symbols will be used in describing thevarious experimental designs:

X = exposure of a group to an experimental treatmentO = observation or measurement of the dependent

variable. If more than one observation ormeasurement is taken, subscripts (that is, O1, O2,

O3,etc. will be given to indicate temporal order.= random assignment of test units. It symbolizes that

individuals selected as subjects for the experiment arerandomly assigned to the experimental groups

The diagrams of experimental designs that follow

R


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Following are the examples of quasi-experimental

designs:

Quasi-Experimental designs do not qualify as trueexperimental designs because they do not

adequately control for the problems associated with

loss of external or internal validity.

1) One- Shot Design (After-Only Design) It is a quasi-experimental design in which a single

measure is recorded after the treatment is

administered and there is no control group.

The one-shot design is diagrammed as follows:

X O1 In this experiment we do not have any kind of

comparison


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2) One-Group Pretest-Posttest Design (Before-After

Design)

It is a quasi-experimental design in which thesubjects in the experimental group are measured

before and after the treatment is administered but in

which there is no control group.

The One-Group Pretest-Posttest Design isdiagrammed as follows:

O1 X O2 It offers a comparison of the same individuals before

and after experimental treatment.

The weaknesses of this experimental design may the

time, cost and internal validity.


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3) Static Group Design (After-Only Design with Control

Group)

In the static group design, subjects are identified as either anexperimental group or a control group.

The experimental group is measured after it has been

exposed to the experimental treatment, and the control

group is measured without having been exposed to the


The Static Group Design is diagrammed as follows:

Experimental Group: X O1

Control Group: O2 The results of the static group design are computed by

subtracting the observed results in the experimental group

from the observed results in the control group. (O2 O1)

A major weakness of this design is that it provides no

2) Pretest-Posttest Control-Group Design (Before-After


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) p g (with Control Group)

It is a true experimental design in which the experimental

group is tested before and after exposure to thetreatment, and the control group is tested at the same

two times without being exposed to the experimental

treatments.

The Pretest-Posttest Control-Group Design is the classicexperimental design, diagrammed as follows:

Experimental Group: O1 X O2Control Group: O3 O4

The effect of the experimental treatment is calculated as

follows:

(O2 O1) (O4 O3)

It is assumed that the effect of all extraneous variables

will be same on both experimental and control groups.

R

R

3) Posttest-Only Control Group Design (After-Only with


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) y p g ( yControl Group)

The Posttest-Only Control Group Design diagrammed as

follows:

Experimental Group: X O1Control Group: O2

The effect of the experimental treatment is calculated as

follows:

O2 O1

It is assumed that the effect of all extraneous variables

will be same on both experimental and control groups.

R

R


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4) Solomon Four-Group Design

Combining the before-after with control group design

and the after-only with control group design, theSolomon four-Group design provides a means for

controlling the testing effect, as well as other sources of

extraneous variation.

The Pretest-Posttest Control-Group Design is the classicexperimental design, diagrammed as follows:

Experimental Group1 : O1 X O2Control Group 1 : O3 O4Experimental Group 2 : X O5

Control Group 2 : O6

R

R

R

R


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5) Compromise Experimental Designs

An approximation of an experimental design, which

may fall short of the requirements of random

assignment of subjects or treatments to groups.

There is no assurance that these naturally occurring

groups are equivalent; the researcher has

compromised because of the nature of the situation.

When the experiment involves a longitudinal study,

circumstances usually dictate a compromise with true

experimentation.


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6) Time-Series Experimental Designs

It is an experimental design utilized when experiments

are conducted over long periods of time. It allows researchers to distinguish between

temporary and permanent changes in dependentvariables.

It is quasi-experimental design, because theygenerally do not allow the researcher full control overthe treatment exposure or the influence of extraneousvariables.

The simple time-series design can be diagrammed asfollows:

O1 O2 O3 X O4 O5 O6 The time-series design cannot give the researcher

complete assurance that the treatment caused the


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One unique advantage of the time-series design is its

ability to distinguish temporary from permanent

changes.An improvement on the basic time-series design is a

time-series with control group design.

For ex: many test markets utilize different geographic

areas, which are similar demographically, as a basisfor experimental control.

2) C l E i t l D i


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2) Complex Experimental Designs

It is an experimental design that uses statistical

methods to isolate the effects of extraneousvariables or to allow for manipulation of multiple

independent variables.

1. Completely Randomized Design

2. Randomized Block Design

3. Factorial Designs

4. Latin Square Design


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1) Completely Randomized Design (CRD)

It is an experimental design that uses a random process to

assign experimental units to treatments in order toinvestigate the effects of a single independent variable.

Randomization of experimental units is the researchers

attempt to control all extraneous variables while

manipulating a single independent variable, the treatmentvariable.

A pretest-posttest with control groups that replicates, or

repeats, the same treatment on different experimental

units is one of the example of CRD. Analysis of Variances (ANOVA) involves investigating the

effects of one treatment variable on an interval-scaled or

ratio-scaled dependent variable. In CRD designs, ANOVA

is the appropriate form of statistical analysis when the


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2) Randomized Block Design (RBD)

It is an extension of the CRD.

The term RBD is derived from agricultural research,

where different levels of a treatment variable are

applied to each of several blocks of land. Systematic

differences in agricultural yields, due to the quality of

the blocks of land, may be controlled in the RBD.

In RBD, a single extraneous variable that might affect

test units response to the treatment has been

identified and the effects of this variable are isolatedby being blocked out.

3) F i l D i


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3) Factorial Designs

It is an experimental design that investigates the

interaction of two or more independent variables.

It allows for testing the effects of two or more

treatments at various levels.

A Main effect is the influence on dependent variableby each independent variable

The Interaction effect is the effect of combiningthese job characteristic variables.

A major advantage of the factorial design is its abilityto measure the interaction effect, which may be

greater than the total of the main effects.

4) L i S D i


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4) Latin Square Design

It is a Balanced, two-way classification scheme that

attempts to control or block out the effect of two or

more extraneous factors by restricting randomization

with respect to row and column effects.

This design is named so because of the layout of the

table that represents the design.

In the 3 X 3 matrix below, each letter occurs only once

in each row and only once in each column.Order of Usag

e

1 2 3

1 A B C

Subject 2 B C A

3 C A B

C f


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The capital letters A, B, and C identify the three

treatments. The rows and columns of the table

identify the confounding factors.

The Latin square design manipulates one

independent variable and controls for two additional

sources of extraneous variation by restricting

randomization with respect to row and column effects.A major assumption of the Latin square design is that

interaction effects are expected to be minimal or

nonexistent.

Having an unequal number of levels for each factormay be a drawback that will eliminate the Latin

square design as a possibility.

A second limitation is the assumption that there is no

module 2 (aagal nu adhuru) (tbm)

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