Dr. Maxwell wants to investigate the effects of caffeine consumption on mathematical ability in middle school girls. She selects a local middle school and has a computer select 50 of the 250 girls at random to be a part of the experiment. The girls are divided into two groups. Each group takes a similar- looking pill and then the girls are given a series of challenging puzzles to solve while Dr. Maxwell keeps track of their scores while solving. At the end of the experiment, Dr. Maxwell concludes that caffeine does boost mathematical performance. Define and explain how each of these terms is used in this experiment in essay form:

Independent Variable
Dependent Variable
Random Assignments
Confounding Variables