Table 2.

Knowledge about dietary supplements among web-based health service users and social networking service users.

Variable	Total sample (N=6273)		Differences between the type of web-based service
			Type of analysisa	Health service users (n=4018), mean (95% CI)	Social networking service users (n=2255), mean (95% CI)	Effect size of the differenceb		Test statistics and P values for the comparison
	Mean	95% CI				pη2 value (%)c	Mean (95% CI)	F test (df)	F test (df)	P value
Knowledge about dietary supplements–Generald	4.4	4.4-4.5
			Raw	4.0 (3.9-4.1)	5.3 (5.2-5.3)	8.7	−1.3 (−1.4 to −1.2)	595.4 (1,6271)	N/Ae	<.001
			Adjusted	4.1 (4.1-4.2)	5.0 (4.9-5.1)	2.0	−0.9 (−1.0 to −0.7)	N/A	129.7 (1,6265)	<.001
Knowledge about dietary supplements–Specificf	4.5	4.5-4.6
			Raw	4.0 (3.9-4.0)	5.5 (5.4-5.6)	13.8	−1.5 (−1.6 to −1.4)	1008.1 (1,6271)	N/A	<.001
			Adjusted	4.0 (4.0-4.1)	5.5 (5.4-5.5)	6.2	−1.4 (−1.5 to −1.3)	N/A	411.9 (1,6265)	<.001
Knowledge about dietary supplements–Totalg	9.0	8.9-9.1
			Raw	8.0 (7.9-8.1)	10.8 (10.7-10.9)	16.5	−2.8 (−3.0 to −2.7)	1237.9 (1,6271)	N/A	<.001
			Adjusted	8.2 (8.1-8.3)	10.5 (10.3-10.6)	5.9	−2.3 (−2.5 to −2.1)	N/A	393.4 (1,6265)	<.001

^aRaw analyses: performed only with the variables reported; adjusted analyses: adjusted for |Age−35|, sex, education, number of inhabitants, earnings, and calendar year—all included as linear factors; estimates in adjusted analyses reported as estimated marginal means.

^bReported as a partial eta-squared (pη²) and a difference between knowledge about dietary supplements of health service users and knowledge about dietary supplements of social networking service users (95% CI).

^cpη²: partial eta-squared.

^dAn expected result of random guess is 3.5.

^eN/A: not applicable.

^fAn expected result of random guess is 5.

^gAn expected result of random guess is 8.5.