1. Describe how extraneous variables can become confounding variables and threaten the internal validity of a research study; identify threats when they appear in a research report. 2. Define...

1. Describe how extraneous variables can become confounding variables and threaten the internal validity of a research study; identify threats when they appear in a research report.

2. Define experimenter bias, demand characteristics, and reactivity, and explain how these artifacts can threaten both internal and external validity