A psychologist develops a behavioral treatment to decrease the frequency of a child's temper tantrums. In order to make a causal interpretation about the effectiveness of the treatment using an ABAB design, the most problematic initial baseline period would show .

a decreasing trend in the number of temper tantrums.

Explanation:

ABAB design also known withdrawal or reversal design is a design used in experimental study of behaviour to measure the effects of a treatment on a particular baseline information by measuring a baseline information A, then applying a treatment B on A, thereafter, treatment B is withdrawn from A for a period, and finally treatment B is applied again to A to measure the effects of change caused by the treatment. This design is given by :

A - baseline established

B - treatment offered

A - withdraw treatment for a time

B - offer treatment again to show effectiveness of the treatment