a) the observer effectb) the bystander effectc) observer biasd) subject b
Answer:
C. Observer bias
Explanation:
We should be most concerned about the observer bias. This is because already, taffi has developed a bias about MacDonald's customers. She already has the belief that they are going to be overweight. So this is going to affect her observations. This effect is known by the name, observer bias. She may subconsciously influence the participants of this study.
