A statistics class wants to know if high school students can memorize passages from novels better when they are read to or when they are reading the passages themselves. The class takes a random sample of 20 students, and each student will have two passages to memorize from the same novel. One passage will be read to the student, while the student will read the other passage themselves. A coin toss will decide the order of the treatments. The class will then find the mean difference in number of words memorized by each student in the two treatments. What is the appropriate statistical test for analyzing the results of this experiment