Experimental research is the most conclusive scientific method because the researcher directly manipulates the independent variable and studies its effects on the dependent variable. This allows the researcher to determine causation, unlike other research methods. The purpose is to establish cause-and-effect relationships between variables. Basic steps include having an experimental group that receives a treatment and a control group that does not, then comparing outcomes. Key characteristics include random assignment to control threats to internal validity. Poor designs do not include control groups or random assignment, making it impossible to determine if results are due to the treatment.

1. +
Experimental
Research
Chapter 13 (page 265)
PREPARED BY
• IZZA ATHIRA BINTI AB JALIL
• NURUL SYAFIQAH MD AMIN
• NUR’IZZAH BINTI MOHAMMED FAUDZAN
• NORASYIKIN MT RASHID

2. +
WHAT is Experimental Research?
 The most conclusive of scientific methods
BECAUSE
The researcher actually establishes different
treatments and then studies their EFFECTS, results
from this type of research are likely to lead to the most
clear-cut interpretations.

3. + Two ways in which Experimental Research
differs from other educational research
Researcher manipulate the independent variable
1. Decide the nature of the treatment
- to whom it is to be applied
- to what extent
2. Enables researchers to go
- beyond description and prediction
- beyond the identification of relationship, to at
least a partial determination of what causes
them.

4. +
CHARACTERISTIC of
Experimental Research

5. CONCEPT
Experimental group
Control group
Comparison group
Random selection
Random assignment
Independent variable
Dependent variable
Extraneous variable
DEFINITION
The group that received a treatment of
some sort in an experiment
The group that does not receive a
treatment in an experiment
The group that receives a different
treatment
A process wherein every member of a
population has an equal chance to be
a member of the sample
Every individual who is participating in
an experiment has an equal chance of
being assigned to any of the
experimental or control conditions
being compared
Researcher chooses to study in order
to assess their possible effect(s) on
one or more other variables
Refers to the result(s) or outcome(s)
being studied
Independent variables that have not
been controlled

6. +
PURPOSE of Experimental
Research
 To establish cause and effect relationship among
variables
 The only type of research that directly attempts to
influence a particular variables
 Correlational studies may demonstrate a strong
relationship between socio-economic level and
academic achievement, for instance

7. +
BASIC STEPS in conducting an
experiment
Formal experiment consist of two conditions :
 At least two conditions or methods are compared to
assess the effect(s) of particular conditions
 The independent variable is directly manipulated by
the researcher.

8. + Various Threats to Internal Validity
Associated with Different Experimental
Design
 Holding certain variables constant
 Building the variable into the design
 Matching
 Using subjects as their own controls

9. +
MANIPULATION of Independent
Variable
 The researcher actively manipulates the
independent variables
MEANS
The researcher deliberately and directly determines
what forms the independent variable will take and then
which group will get which form.

10. +
THREE WAYS in
such the
manipulation can
occur
1. One form of variable versus another
 E.g. : Comparing the inquiry method
with the lecture method of instruction
in teaching chemistry
2. Presence versus absence of a
particular form
 E.g. : Comparing the use of power
point slides versus no power point
slide in teaching statistic
3. Varying degrees of the same form
 E.g. : Comparing the effects of
different specified amounts of
teacher enthusiasm on student
attitudes towards mathematics

11. +
Group Design in Experimental
Research
 Good designs control many of the various threats to
internal validity (chapter 9) while poor designs control
only a few.
 The quality of an experiment depends on how well the
various threats to internal validity are controlled.
 The essential ingredient of a true experimental design is
that subjects are randomly assigned to treatment groups.
 Random assignment is a powerful technique for
controlling the subject characteristics threat to internal
validity

12. +
Example of Poor Experimental
Design
 The one-Shot Case Study
 The obvious weakness of this design is :
X
Treatment
(Treatment of Interest)
O
Observation
(Dependent variable)
- absence of any control
- does not provide for any comparison
- no way of knowing if the result obtained at O
are due to treatment (X)

13. +
Example of Poor Experimental
Design
 The One-Group Pretest-Posttest Design
X
Treatment
10 weeks
of counseling
O
Pretest:
20 item attitude
scale completed
by students
O
Posttest:
20 item attitude
scale completed
by students
 Better than one-shot case study because researcher at least
know whether any changes occurred
 Threats to internal validity exist and may influence the outcome
of the study

14. +
Example of True Experimental
Design
 The Randomized Posttest-Only Control Group Design

15. +
Example of True Experimental
Design
 The Randomized Pretest-Posttest Control Group Design

16. +
QUESTIONS :
1. Why experimental research is different than any
other educational research?
2. What is the purpose of experimental research?
3. Describe the basic steps involved in conducting an
experimental research?
4. What is one of experimental research
characteristic?
5. Explain how to identify poor experimental design?