Please check this, I think it may be age too. I got this marked wrong. The other person said Race was the answer.

Lillehei et al. (2015) studied the effect of inhaled lavender and sleep hygiene on self-reported sleep issues in college students. They divided participants into two groups. One group (the LSH group) received a lavender patch with sleep hygiene and the other group (the SH group) received a blank (placebo) patch with sleep hygiene. The table below describes the demographic and clinical characteristics of the sample. Given a level of significance of 0.05, for which variables did the authors conclude there was a statistically significant difference between the two groups? (Select all that apply) TABLE 1. DEMOGRAPHIC AND CLINICAL CHARACTERISTICS OF PARTICIPANTS Lavender patch + sleep Blank patch + sleep hygiene Total Characteristic hygiene (LSH group) (n = 39) (SH group) (n=40) (n =79) Age, mean (range), years 20.9 (18-28) 22.1 (18-36) 21.6 (18-36) 0.09" Gender, n (%) 9.46 Female 25 (64) 29 (73) 54 (69) Male 14 (36) 10 (25) 24 (30) NA 0 (0) 1 (2) 1 (1) Race, n (%) 0.02 White 24 (62) 29 (73) 53 (67) Black or African American 0 (0) 2 (5) 2 (3) Asian 13 (33) 4 (10 ) 17 (22) American Indian or Alaskan Native 0 (0) 1 (2 ) I (1) Other 0 (0) 1 (2) 1 (1) NA 2 (5) 3 (8) 5 (6) Ethnicity, n (*) 0.340 Not Hispanic or Latino 36 (92) 31 (78) 67 (85) Hispanic or Latino 1 (3) 3 (7) 4 (5) NA 2 ( 5 ) 6 (15) 8 (10) Health conditions, n (9%) 0.18 No 34 (87) 29 (73) 63 (80) Yes 5 ( 13) 11 (27) 16 (20) 1-test. "Chi square. "Fisher's exact test. "Health conditions reported: depression (n=4), allergies (n= 3), asthma (n =3), anxiety (n=2), ADHD (n=2), overweight (n = 1). hypertension (n = 1). epilepsy (n = 1), cyclothymia (n= 1), and vitamin D deficiency (n= 1). Some participants reported more than one condition. O Age Gender Race O Ethnicity O Health Conditions