What is the advantage of researchers using an empirical approach in evaluating the accuracy of eyewitness testimony?

Facial shaving brushes are either bulb-shaped or fan-shaped. an experiment is to be conducted to determine whether the lather thickness is the same for both types of shaving brushes. in previous studies, it was determined that shaving brush size (small, medium, large) is associated with lather thickness, but shaving brush type (wolf whiskers, maggard razors, frank shaving, and so on) is not associated with lather thickness. how could the experiment best be conducted? by blocking on shaving brush size by blocking on shaving brush type by blocking on shaving brush shape by blocking on lather thickness without blocking

Which presentation option is also known as a screen of a presentation?

Why is the road most slick when it first begins to rain? a. oils the road has absorbed begin to float. b. the water has not had time to run off. c. a higher concentration of dirt makes the road more slick. d. none of the above