On a statistics examination, an instructor finds that SD = l4.0 for a sample of undergraduate test scores and SD = 7.0 for a sample of graduate test scores. Both samples have the same number of students. Which of the following statements is warranted? Group of answer choices Undergraduates did better by 7 points. Graduates are more heterogeneous in performance than graduate students. Undergraduates are more homogeneous in performance than graduate students. Undergraduates are more heterogeneous in performance than graduate students