Agre course prep company advertises that its course can significantly raise students gre verbal reasoning scores. in order to assess the accuracy of this claim, a researcher randomly selected a sample of 30 graduating seniors from a local university, who are applying to business school. the 30 students first took the gre, without any preparation. the 30 students then took the gre again, after completing the gre prep course. the researcher then compared the performance for each student to determine whether there was improvement on the gre verbal reasoning scores from the first to second administrations. what hypothesis testing technique should the researcher use to analyze the data? a) anovab) z-test for the population meanc) two-sample t-testd) paired t-test