Table 1.

Means and standard errors for demographics, questionnaire results, and CO levels, separated by group

Means and standard errors of questionnaires
	Non-smoker mean (SE)	Smoker mean (SE)	t
Caucasian	84 %	81 %
Male	56 %	61 %
Educationa	3.13 (0.22)	2.65 (0.17)	1.68+
Age (years)	38.38 (2.79)	36.90 (2.51)	0.39
Monthly income ($)	2,080 (301)	2,055 (447)	.047
Information Inventory	10.13 (0.58)	8.52 (0.63)	1.88
MASTb	3.00 (0–8)	12 (0–33)	197.00*
SOGSb	0.00 (0–1.75)	1.00 (0–5)	292.50*
CO (ppm)	1.97 (0.13)	9.35 (0.34)	−20.15c*

^aEducation was measured using seven categories and participants were asked about their highest level of obtained education: 1 = did not complete high school, 2 = high school degree or equivalent, 3 = associate degree, 4 = bachelors degree, 5 = graduate degree, 6 = doctorate degree or equivalent

^bMedian and interquartile ranges (25 % and 75 % percentiles) reported instead of mean and standard error. Shapiro–Wilk test for normality indicates that scores are not normally distributed. Non-parametric Mann–Whitney U-test reported in place of t-test

^cViolation of Levene’s Test for Equality of Variances, equal variances not assumed

*p < 0.05