A school psychologist wants to test the effectiveness of a new method of teaching . She recruits -grade students and randomly divides them into two groups. Group 1 is taught by means of the new method, while group 2 is taught by traditional methods. The same teacher is assigned to teach both groups. At the end of the year, an achievement test (graded on a scale from 1-10) is administered and the results of the two groups are compared. Complete parts (a) through (i) below.