During the last three decades of the 20th century, the number of _____ students in U.S. public schools almost tripled, while the number of _____ students dropped

When people hear a sound, their ears turn the vibrations in the air into neural messages from the auditory nerve, which makes it possible for the brain to interpret the sound. This process is called __________

a) encoding b) storage c) retrieval d) evaluation

Which of the following variables is presumed to vary as a result of the researcher's manipulation of another factor or condition?

a) control b) dependent c) independent d) random