When Events That Occur During the Course of a Study

question 13

Multiple Choice

When events that occur during the course of a study have a different effect on one group of participants than on another,the possible threat to internal validity is

• A) differential regression.
• B) selection.
• C) history.
• D) additive effects of selection and history.

---

Definitions:

UV Light

Ultraviolet light, a type of electromagnetic radiation with a wavelength shorter than that of visible light but longer than X-rays, affecting living tissues.

Radiographically Labeled

Marked or tagged with a radiographic marker for visualization under X-rays or similar imaging techniques.

Blotting Buffer

A solution used in molecular biology techniques to transfer proteins, DNA, or RNA onto a membrane for detection and analysis.

UV Light

Ultraviolet light, a type of electromagnetic radiation which is not visible to the human eye and has shorter wavelengths than visible light but longer than X-rays.