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Experimental ResearchChapter 13 (page 265)

PREPARED BY• IZZA ATHIRA BINTI AB JALIL• NURUL SYAFIQAH MD AMIN• NUR’IZZAH BINTI MOHAMMED FAUDZAN• NORASYIKIN MT RASHID

+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.

+Two ways in which Experimental Research differs from other educational researchResearcher 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.

+CHARACTERISTIC of Experimental Research

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

+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

+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.

+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

+MANIPULATION of Independent Variable

The researcher actively manipulates the independent variables

MEANSThe researcher deliberately and directly determines what forms the independent variable will take and then which group will get which form.

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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

+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

+Example of Poor Experimental Design

The one-Shot Case Study

The obvious weakness of this design is :

XTreatment

(Treatment of Interest)

OObservation

(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)

+Example of Poor Experimental Design

The One-Group Pretest-Posttest Design

XTreatment10 weeks

of counseling

OPretest:

20 item attitude scale completed

by students

OPosttest:

20 item attitudescale 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

+Example of True Experimental Design

The Randomized Posttest-Only Control Group Design

+Example of True Experimental Design

The Randomized Pretest-Posttest Control Group Design

+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?