Table 1.

Selection probabilities for observing food intake in school, according to some demographic characteristics, BMI and access to Internet at home, among schoolchildren (n 629), aged 7–11 years, attending 2nd to 5th grades of five elementary public schools in Florianopolis, Brazil, March–October 2012

	Morning snack		Lunch		Afternoon snack		Weighted mean
Characteristic	N *	%†	N *	%†	N *	%†	%†
School grade
2nd and 3rd	137	27.74‡	152	36.18‡	64	10.94‡	28.33‡
4th and 5th	125	8.80‡	217	11.52‡	63	31.75‡	13.83‡
Sex
Boys	129	17.83	165	58.93‡	63	17.46	21.85
Girls	133	19.55	204	36.36‡	64	25.00	19.45
BMI quintile (WHO Z-score)
1 (<−1.70)	45	24.54	80	13.75	21	23.81	18.49
2 (−1.71, −0.70)	58	12.07	59	32.20	29	13.79	20.55
3 (−0.71, 0.25)	50	14.00	63	22.22	32	12.50	17.24
4 (0.26, 1.54)	49	18.70	74	20.05	23	18.11	19.26
5 (>1.54)	49	20.41	80	22.50	16	25.00	22.07
Missing	11	45.45	13	23.08	6	50.00	36.67
Family income (quintiles)
1	17	17.65	35	22.86‡	11	36.35	23.81
2	99	22.22	143	11.19‡	57	19.30	16.39
3	53	13.21	73	23.29‡	11	27.27	19.71
4	29	24.14	20	25.00‡	9	11.11	22.41
5	9	0.00	18	22.22‡	1	100.00	17.86
Missing	55	18.18	80	37.50‡	38	18.42	27.17
Highest parental education level
Elementary	73	17.81‡	113	19.47‡	34	26.47	20.00
High school	97	25.78‡	134	18.66‡	31	9.68	20.23
College	37	2.70‡	44	9.09‡	22	27.27	10.68
Missing	55	18.18‡	78	37.18‡	40	22.50	27.75
Child’s access to Internet at home
No	71	19.72	95	17.89	54	27.78	20.91
Yes	152	17.10	232	18.53	55	14.55	17.54
Missing	39	14.89	42	11.38	18	14.17	18.06

^*Number of children observed for a given school meal.

^†Probability of observing a child with a given characteristic (percentage).

^‡Hypothesis of equal percentages rejected by χ² test (P<0.05).