EXPERIMENTAL RESEARCH CHAPTER 13 Presented by : Nurul Ain binti Abd Manan 2013160689 Nor Zakiah binti Ismail 2013741249 Siti Khalijah binti Zainol 2013977165
EXPERIMENTAL RESEARCHCHAPTER 13
Presented by :Nurul Ain binti Abd Manan 2013160689
Nor Zakiah binti Ismail 2013741249
Siti Khalijah binti Zainol 2013977165
Traditional type of research EXPERIMENTAL RESEARCH concerns relationships between
variables Purpose is to investigate cause-and-effect relationships
among variables• Experimental groups vs. control groups• Each group of participants receives a different treatment• Always involves manipulation of the independent variable
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
EXPERIMENTAL RESEARCH
STEPS IN EXPERIMENTAL RESEARCH
State the research problem Determine if experimental
methods apply Specify the independent
variable(s) Specify the dependent
variable(s) State the tentative hypotheses Determine measures to be used Pause to consider potential
success
Identify intervening (extraneous) variables
Formal statement of research hypotheses
Design the experiment Final estimate of potential
success Conduct the study as planned Analyze the collected data Prepare a research report
UNIQUENESSEXPERIMENTAL RESEARCH
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 extent2. Enables researchers to go
- beyond description and prediction
- beyond the identification of relationship, to at least a partial determination of what causes them.
CHARACTERISTIC OF EXPERIMENTAL RESEARCH
CONTROL OF EXTRANEOUS VARIABLES
Researchers who conduct experimental studies try to control any and all the subject characteristics.
There are some common ways that had been used by researchers to minimize or eliminate threats
WAYS TO MINIMIZE OR ELIMINATE THREATSRandomization : assume the groups are equivalentHolding certain variable constant : eliminate the possible
effectsBuilding the variable into design : include as distinct groupMatching : pairs subjects matched to certain variablesUsing subjects as their own controls :compared the
performance Using analysis of covariance : equate groups
statistically on the basis of pretest or other variables
GROUP DESIGNS 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.
POOR EXPERIMENTAL DESIGNS
One-Shot Case Study DesignIt does not provide for any comparison, so the
researcher cannot compare the treatment results (as measured by the attitude scale) with the same group before using the new textbook, or with those of another group using a different textbook.
The researcher knows nothing about what the group was like before using the text.
POOR EXPERIMENTAL DESIGNS
One-Group Pre test-Post test Design
This design is better than the one-shot case study (the researcher at least knows whether any change occur).
Nine uncontrolled-for threats (history, maturation, instrument decay, data collector characteristics, data collector bias, testing, statistical regression, attitude of subjects, and implementation).
The researcher would not know if any differences between pretest and posttest are due to the treatment or to one or more of these threats.
TRUE EXPERIMENTAL DESIGNS
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
The randomized posttest-only control group design involves two groups formed by random assignment.
The randomized pretest-posttest control group design differs from the randomized posttest-only control group design only in the use of a pretest.
TRUE EXPERIMENTAL DESIGNS
TRUE EXPERIMENTAL DESIGNS
EVALUATING THE LIKELIHOOD OF A THREAT
The important consideration in planning an experimental study.
A number of possible threats may exist.The must ask question by the research is :
How likely is it that any particular threat exist in this study?
AID IN ASSESSING THE LIKELIHOODStep 1 : What specific factors either are
known to affect the dependent variable or may logically to be expected to affect this variable?
Step 2 : What is the likelihood of the comparison groups differing on each of these factors?
Step 3 : Evaluate the threats on the basis of how likely they are to have an effect, and plan to control for them.
THREATS TO INTERNAL VALIDITY
Subject characteristics
MortalityLocationInstrumentationTesting
HistoryMaturationAttitude of SubjectsRegressionImplementation
CONTROL OF EXPERIMENTAL TREATMENTS
Intended to improve the internal validity.It has advantages and disadvantages.The researcher control over the experimental
treatments- what, who, when and how of it.Researchers seldom have control in educational
research.
QUESTIONS
1)What is experimental research?
2)What are the uniqueness of experimental research?
3)How does the experimental research differ from other type of research?
4)What is random assignment, and what is the difference between random assignment and random selection?
5)How to describe poor experimental design?