The cognitive gains needed for such tasks as balancing a scale with weights by trial and error are usually acquired during adolescence

What is a single-case design?

a) A design that administers different conditions to different subjects over time b) A design that administers the same condition to the same subject over time c) A design that administers the same conditions to different subjects over time d) A design that administers different conditions to the same subject over time

Which of the following is a potential source of error in a measure?

a. The way an item is phrased b. Variations in an observer's attention c. Distractors present when observations are made d. All of these answers are correct