The first command below creates a variable called PRETEST that is the set of pretest scores for a class. The second command below creates a variable called POSTTEST that is the set of posttest scores for a class.

PRETEST <- c(0,0,1,1,1,1,1,1,2,2,2,2,2,3,3,3,3,4,4,4) POSTTEST <- c(2,1,2,1,2,3,2,4,5,5,3,1,0,5,2,2,3,5,5,4)

Below, enter an R command that you draft that can be used to calculate the p-value for a test of the null hypothesis that the mean pretest score among the class (PRETEST) equals the mean posttest score among the class (POSTTEST); the code for the statistical test should explicitly not pair a student's pretest score to the student's posttest score.