2009/06/08

Experimental Research Methodologies

Discuss the different types of experimental research methodologies used in science research(taken from the learning competencies of Research II Special Science Curriculum).

Experimental research method - is a scientific method of investigation to test the scientific hypothesis. It involves a careful steps that considers the internal and external validity to solve a problem.

internal validity- is having a consistent result from an experimental observation no matter how many times you repeat the same procedure.
The 8 threats to internal validity are history, maturation, testing, instrumentation, statistical regression, selection biases,experimental mortality and selection x maturation interaction.


example: The use of randomizing experimental samples and increasing the number of trials strengthen internal validity.

External validity- is having a result that is always true even the experiment is tested to other people or on a slightly different condition.
The 4 threats to external validity are: Reactive or interactive effects of testing, Interaction of selection biases and experimental treatment, Reactive effects of experimental arrangements, and Multiple treatment interference.

example: To test the external validity of an observation:vinegar can curdle milk is to try another acid, like muriatic acid.

Students in the Philippines are hindered when conducting an experimental research because of financial limitation. Of course there is a way where they can tailor fit their research depending on the availability of resources and at the same time not omitting the importance of external and internal validity. They can choose from the three different types of experimental research methodologies:

1. True experimental research method- employs random selection of samples and assignment of control, experimental groups and conditions.

2. Quasi-Experimental research method- similar to true experimental design but without the use of random selection of control and experimental group.

3. Pre-Experimental research method- employs single group without random selection.

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