Ted treated participants in one condition of his experiment differently from participants in another condition.This difference in the treatment was not part of the experimental design.What did Ted's behaviour most likely decrease?
A) the probability that the results of the study would be statistically significant
B) the chances that experimenter expectancy effects would be produced
C) the internal validity of the results
D) the experimental realism of the procedures

Question

Quizplus · Accepted Answer

Ted's behavior decreased the internal validity of the results because by treating participants differently, he introduced a confounding variable that was not accounted for in the experimental design. This makes it difficult to draw clear conclusions about the relationship between the independent variable and the dependent variable, thus decreasing the internal validity of the study.

Ted Treated Participants in One Condition of His Experiment Differently