Does music hinder or help performance in math? Researchers designed an experiment using 30 student volunteers to find out. Each subject completed a 50 digit arithmetic test with and without music playing. For each subject, the order of the music and no music treatments were randomly assigned, and the time to complete the test in seconds was recorded for each treatment. Here are the data:

Student	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Time with music	83	119	77	75	64	106	70	69	60	76	47	97	68	77	48	78	113	71	77	37	50	58	52	47	71	146	44	53	57	39
Time without music	70	106	71	67	59	112	83	69	65	83	38	90	76	68	50	73	93	59	70	39	52	60	54	51	60	141	40	56	53	37

Construct and interpret a 90% confidence interval for the mean difference of test completion time, with and without music.