Question

You are curious about whether you can enhance the ability to hear differences between nonnative speech sounds when people learn a new language. You test your novel language training procedure on a group of 32 pariticipants using a pretest/posttest design. The pretest and the posttest measure performance as the number of correct trials out of 100. The data are shown on the right. Does the new language training procedure improve the perception of nonnative speech sounds?

	Number of correct items
Participant	pretest	posttest
1	50	64
2	38	51
3	50	64
4	48	53
5	41	41
6	35	40
7	51	66
8	41	42
9	31	41
10	45	47
11	35	40
12	21	27
13	21	25
14	45	46
15	35	40
16	48	53
17	31	42
18	31	34
19	31	38
20	45	47
21	45	43
22	30	29
23	48	53
24	31	29
25	28	49
26	40	62
27	31	34
28	48	53
29	50	64
30	38	51
31	15	35
32	18	46

Answer 1