Principle Of Experiments Threats

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Principle Of Experiments Threats

Principle Of Experiments Threats

Answer# 1

As students, we have been frequently involved, for instance, in making inference or drawing a conclusion in our daily academic activity such as doing research or conducting an experiment from which the conclusion or inference will be drawn and written up as a research paper or thesis or dissertation. For instance, after conducting a research on whether the math improvement program at the 7 graders have really made change in the post test, one might concludes that the program has absolutely elevated the average score on the post test. How valid is this conclusion? How close to the truth is this conclusion? Was the program really responsible for that change in post test score of the students? All these question are concerned with what is called VALIDITY.

Answer# 2

There are four types of validity in social research -- construct validity, conclusion validity, external validity and internal validity. In this assignment, only the internal validity is considered in more explanatory and hopefully in a pedagogical ways.

What is internal validity? Internal validity is the approximate truth the inference is made regarding the study that involves a causal relationship (Trochim, 1999).

From the earlier example, the math improvement program has tried to elevate the average post test score of the 7 graders. Internal validity in this example has something to do with how close your inference or conclusion regarding the truth that only your program has made such improved grades that the students have received at the post test. There might be some other factors that are instead responsible for making or contributing to such improvement. They might get the good grades because they feel very good during the day they took a test or they might get the poor grades because during the time you were taking the test they were interrupted by outside traffic or they have not eaten breakfast or lunch ( I've experienced this myself. I lost 50% of my concentration).

Answer# 3

The set of factors that prevent us from assuring that the improved average score at the post test is due to our program as mentioned above is called plausible alternative explanation. Put differently, they are frequently termed as threats to internal validity. These threats inhibit most researchers or scientists from making internally valid inference or conclusion from their research or experiment unless their researches or experiments are designed in a way that would rule them out.

What is threats to internal validity? Threats to internal validity is refereed to all alternative causes other than the program or treatment that are responsible for the difference in the post test. These threats would prevent researchers or scientists who are trying to study causal relationship within their treatment or program from detecting the real effect of that program. In other word, the threats to internal validity prevent researchers or scientists from establishing the real causal relationship in their program (Trochim, 1999). For instance, you are implementing a program which is ...
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