Post on 04-Apr-2018
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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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The Nature Of Observation Studies
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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The Nature Of Observation Studies
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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4) Measuring Physiological Reactions
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 by SMI Bee Swarm TVCommercial.mp4
http://localhost/var/www/apps/conversion/tmp/scratch_10/Eye%20Tracking%20by%20SMI%20Bee%20Swarm%20TV%20Commercial.mp4http://localhost/var/www/apps/conversion/tmp/scratch_10/Eye%20Tracking%20by%20SMI%20Bee%20Swarm%20TV%20Commercial.mp4http://localhost/var/www/apps/conversion/tmp/scratch_10/Eye%20Tracking%20by%20SMI%20Bee%20Swarm%20TV%20Commercial.mp4http://localhost/var/www/apps/conversion/tmp/scratch_10/Eye%20Tracking%20by%20SMI%20Bee%20Swarm%20TV%20Commercial.mp47/29/2019 Module 2 (Aagal Nu Adhuru) (TBM)
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4) Measuring Physiological Reactions
Eye Tracking Monitors
PUPILOMETERS
Psychogalvanometers
Voice Pitch Analyzers
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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4) Measuring Physiological Reactions
Eye Tracking Monitors
Pupilometers
PSYCHOGALVANOMETE
RS
Voice Pitch Analyzers
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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4) Measuring Physiological Reactions
Eye Tracking Monitors
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
experimental treatment.
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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
experimental treatment.
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