Define Internal Validity in Research Design

question 33

Essay

Define internal validity in research design. Describe two threats to the internal validity of a research study. (Note: For each threat, be sure to label it, describe it, and be sure to indicate how it specifically is a threat to the internal validity of the design.)

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Definitions:

Treatment Group

In experimental research, a group of subjects who receive the treatment or intervention under study.

Placebo Group

A control group in an experiment that receives an inert treatment or substance (placebo) to compare against the effects of the active treatment on the experimental group.

Independent Random Samples

This term describes a statistical method in which each member of a set has an equal probability of being chosen, and the selection of one member is made without influencing the selection of any other member.

Significance Level

The threshold at which researchers decide whether an effect or result observed in data is statistically significant, commonly set at 0.05 or 5%.