Do SAT coaching classes work? Do they help students to improve their test scores? In a study, for eight students taking the SAT exam a second time, the improvements in test scores over the first exam were recorded. Four of these students took an SAT coaching class. The other four students did not.

	Improvement
	1	2	3	4
Coaching class	90	100	-30	40
No coaching class	10	80	70	-20

We would like to test the claim that the coaching class improves test scores. The test statistic for this test is

Select one:

a.

-0.39

b.

0.39

c.

15.00

d.

-15.0