Note: * Precertification of denosumab (Prolia and Xgeva) is required of all Aetna participating providers and members in applicable plan designs. For precertification of denosumab (Prolia and Xgeva), call (866) 503-0857, or fax (866) 267-3277.
Observer Expectancy Effect. The observer expectancy effect, also called the experimenter expectancy effect, is a phenomenon that can occur when a researcherâs beliefs or expectations cause him or her to unconsciously influence the participants of an experiment. In order to conserve the internal validity of an experiment, researchers can use a double-blind experimental design.
What are dependent variables and controlled variables? In an experiment, the independent variable is altered, and the effect observed is the dependent variable, or outcome. The controlled variable is intended to be kept the same tâ¦hroughout the experiment so that changes in it do not affect the results. 2 people found this useful.