2. Introduction
Experiment
Experiments are used to study causal
relationships. Researcher manipulate one or
more independent variables and measure their
effect on one or more dependent variables.
3. Conti…
Experimental Study
Experimental study/research is defined
as “experimental research is a scientific
method of conducting research using two
variables: independent and dependent. It
includes a hypothesis, a variable that can be
manipulated by the researcher, and variables
that can be measured, calculated and
compared.”
4. Conti…
Experimental design means creating a set of
procedures to systematically test a hypothesis.
Most importantly, experimental research is
completed in a controlled environment. The
researcher manipulates the independent
variables to see its effect on dependent
variables. (Harland, 2011)
5. Steps in Experimental Research
There are main five steps in experimental
research.
i. Selecting and defining the problem/ Variables
ii. Write your hypothesis
iii. Design your experimental treatments
iv. Assign your subjects to treatment groups
v. Measure your dependent variable (Bevans,
2019).
6. Conti…
Step 1- Define your problem/ variables
Research Question, Example: Phone use and sleep
Specifically, you ask how the number of minutes a
person uses their phone before sleep affects the
number of hours they sleep.
Independent Variable Dependent Variable
Minutes of phone
use before sleep
Hours of sleep per
night
8. Conti…
Step 2: Write your Hypothesis
Null Hypothesis Alternate Hypothesis
Phone use before sleep
does not correlate with
the amount of sleep a
person gets.
Increasing phone use
before sleep leads to a
decrease in sleep.
9. Conti…
Step 3: Design your experimental treatments
Researcher can choose to treat phone use as:
a categorical variable: either as binary (yes/no)
or as levels of a factor (no phone use, low
phone use, high phone use).
a continuous variable (minutes of phone use
measured every night).
10. Conti…
Step 4: Assign your subjects to treatment groups
Then Researcher need to randomly assign your
subjects to treatment groups. Each group receives a
different level of the treatment (e.g. no phone use, low
phone use, high phone use).
Researcher should also include a control group, which
receives no treatment.
Randomized Design
Subjects are all randomly assigned a level of phone
use using a random number generator.
11. Conti…
Step 5: Measure your dependent variable
In Researcher’s experiment about phone use
and sleep, researcher could measure dependent
variable in one of two ways:
OAsk participants to record what time they go
to sleep and get up each day.
OAsk participants to wear a sleep tracker.
12. Uses of Experimental Research
Design
Experimental research design can be majorly
used in physical sciences, social sciences,
education and psychology. It is used to make
predictions and draw conclusions on a subject
matter.
13. Conti…
Some uses of experimental research design are
highlighted below.
Medicine
Education
Human Behavior
14. Types of Experimental Research
Design
Types
of
Experimental
Research
Design
Pre Experimental Research Design
Quasi Experimental Research Design
True Experimental Research Design
15. Pre-experimental Research Design
In pre-experimental research design, either a group
or various dependent groups are observed for the
effect of the application of an independent variable
which is presumed to cause change. It is the
simplest form of experimental research design and
is treated with no control group. It has no control
over the extraneous or situational variables.
16. Conti…
Extraneous variables
Research Topic: to study the effect of heuristic teaching
method on students learning.
Independent Variable: Heuristic teaching method
Dependent Variable: Students learning
Extraneous Variables: Classroom environment, students
intelligence level, students health related problem etc.
17. Types of Pre-Experimental
Research Design
One-shot Case Study Research Design
One-group Pretest-posttest Research
Design
Static-group Comparison
18. One-shot Case Study Research Design
A single group is given treatment and then tested.
X O
treatment observation
Students Tuition Grades
19. One-group Pretest-posttest Research
Design
A Single Intact group is tested before and
after the treatment.
O1 X O2
Example: Research Topic- study the effect of
heuristic teaching methods on students
learning.
20. Conti…
Step I Step II Step III
Measure
students
learning before
teaching them
through
heuristic
method
Teach students
through
heuristic
method
Measure
Students
learning after
teaching them
through
heuristic
method
Pre Test Applying IV
and DV
Post Test
22. Conti…
Research Topic: study the effect of heuristic teaching
method on students learning.
First Step: Researcher select a group of students and
ensures that these students are equivalent in all aspects.
2nd Step: Divide these students in two groups
i. 1st Group ii. Experimental group
Teach them through
traditional method
Teach them through
Heuristic method
23. Quasi-experimental Research Design
The quasi-experimental research bearing a
resemblance to the true experimental research,
but not the same. A quasi-experimental design aims
to establish a cause-and-effect relationship between
an independent and dependent variable. In quasi-
experiments, the participants are not randomly
assigned, they are used in settings where
randomization is difficult or impossible.
24. Types of Quasi Experimental Design
Times Series
Nonequivalent Group Design
Counterbalanced Design
25. Time Series
In this design, researchers track participants for a
lengthy period, both pre-intervention and post-
intervention. A series of test over time(O1 through O4
in this case). Expose group to the treatment and then
measure the subjects with another series of test. (O5
through O8). Examples: Climate Change, Stock
Marketing, School daily attendance.
26. Nonequivalent Group design
This design uses a pretest and posttest for
participants to gauge cause and effect. Subjects are
tested in existing or “intact” groups rather than
being randomly selected. Both groups are
measured before and after the treatment. Only one
group receive the treatment.
27. Counterbalanced
Subjects are not randomly selected but used in
intact groups.
Group 1 receives treatment 1 and test 1. then at
later time they receive the treatment 2 and test
2. Group 2 receives treatment 2 first and then
treatment 1.
Time 1 2
Group 1 X1 O X2 O
Group 2 X2 O X1 O
28. Conti…
Example
Let’s say your study for depression had two
treatments:
Counseling and meditation
Meditation and Counseling
29. True Experimental Research
Design
The true experimental research design relies on
statistical analysis to approve or disprove a
hypothesis. It is the most accurate type of
experimental design and may be carried out with
or without a pretest on at least 2 randomly
assigned dependent subjects.
30. Conti…
The true experimental research design must
contain a control group, a variable that can be
manipulated by the researcher, and the
distribution must be random.
31. Characteristics of True Experimental
Research Design
Manipulation
Randomization
Control
32. The Classification of True
Experimental Design
The posttest-only Control Group Design
The pretest-posttest Control Group
Design
Solomon four-group Design
33. The posttest-only Control Group Design
Subjects are randomly selected and assigned to
two groups. Due to randomization the groups
are statically equal. No pretest is given. One
group receives the treatment.
Students who participated in chess game, they
received higher math scores than who did not.
X O
O
34. The Pretest-Posttest Control
Group Design
In this research designs, subjects are randomly
assigned to either the experimental and the control
group.
The effect of the dependent variable on both the
groups is seen before the treatment (pretest). Later,
the treatment is carried out on experimental group
only, & after-treatment observation of dependent
variable is made on both the groups to examine the
effect of the manipulation of independent variable on
dependent variable.
35. Conti…
O X O
O O
Example: A teacher splits randomly assigns half of
her class to a control group and the other half to
treatment group. She then uses the standard
teaching technique and a new teaching technique
with each group for one week and then administers
the post test.
36. Solomon four-group Design
There are two experimental groups
(experimental group 1 & experimental group
2) & two control groups (control group 1 &
control group 2).
The Solomon design is actually a combination
of the Pre-Test, Post-Test Design (groups 1
and 2) and the Post-Test Only Design (Groups
3 and 4).
38. Methods of Data Collection in
Experimental Research
Observations
Simulation
It is frequently used when the actual situation is too
expensive, dangerous, or impractical to replicate in real
life.
Surveys
39. Advantages of Experimental
Research
Researchers have a stronger hold over
variables to obtain desired results.
The results are specific.
It can be used in different fields.
After analyzing the results, you can apply
your findings to similar ideas or situations.
Researcher can identify the cause and effect
of hypothesis.
40. Disadvantages of Experimental
Research
It is expensive.
It is a time-consuming process.
Experimental research results are not descriptive.
There is no control on extraneous variables.
