This Viennese physician, using ideas originating in his work with mentally disturbed patients, developed the psychodynamic principles of motivation. Who is he?

In Piaget's pendulum task, the solution that reveals whether not an individual is in the formal operations stage is ____

a. the length of the string b. the height from which the weight is dropped c. the force with which it is dropped d. the weight of the pendulum

Samples of size n = 9 are selected from a population with ? = 80 with ? = 18 . What is the standard error for the distribution of sample means?

a. 80 c. 6 b. 18 d. 2