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. Author manuscript; available in PMC: 2008 Sep 22.
Published in final edited form as: Int Labour Rev. 2007;146(3-4):217–251. doi: 10.1111/j.1564-913X.2007.00014.x

Appendix table C.

Standard errors corresponding to percentages in table 21

Salvador
 São Paulo
 Porto Alegre
Age: 10-12 13-14 15-16 10-12 13-14 15-16 10-12 13-14 15-16
Boys (1982-84)
Percentage employed 0 months 0.46 0.81 1.08 0.30 0.71 1.02 0.24 0.81 1.15
Average percentage employed each month 0.26 0.51 0.96 0.22 0.64 1.26 0.18 0.78 1.37
 Low SES2 0.29 0.64 1.16 0.27 0.87 1.66 0.25 1.04 1.80
 High SES3 0.53 0.76 1.68 0.37 0.95 1.93 0.24 1.18 2.11
Percentage employed at least 1 month 0.46 0.81 1.08 0.30 0.71 1.02 0.24 0.81 1.15
 Low SES2 0.49 0.86 1.11 0.33 0.75 1.03 0.23 0.88 1.18
 High SES3 0.38 0.68 0.98 0.25 0.66 1.00 0.26 0.69 1.09
Percentage employed 1 month 4.39 3.23 2.11 5.27 2.82 1.37 8.60 3.24 1.71
Percentage employed 2 months 3.93 2.81 1.90 4.38 2.54 1.12 5.68 2.97 1.51
Percentage employed 3 months 2.55 2.19 1.70 3.45 2.13 1.22 6.71 2.52 1.45
Percentage employed 4 months 1.93 1.38 1.39 3.58 2.39 1.61 5.68 3.17 1.97
Percentage with 1 transition 4.34 3.26 2.11 5.27 2.86 1.48 8.37 3.34 1.84
Percentage with 2 transitions 4.44 3.16 2.00 4.60 2.56 1.27 8.70 2.99 1.54
Percentage with 3 transitions 2.66 1.74 1.09 2.41 1.15 0.44 0.00 1.50 0.65
Girls (1982-84)
Percentage employed 0 months 0.30 0.56 0.81 0.22 0.53 0.90 0.22 0.57 1.04
Average percentage employed each month 0.10 0.36 0.65 0.13 0.46 0.97 0.15 0.51 1.14
 Low SES2 0.10 0.32 0.58 0.13 0.47 0.96 0.15 0.52 1.14
 High SES3 0.04 0.22 0.52 0.13 0.43 0.98 0.13 0.47 1.14
Percentage employed at least 1 month 0.30 0.56 0.81 0.22 0.53 0.90 0.22 0.57 1.04
 Low SES2 0.40 0.73 1.00 0.30 0.80 1.25 0.33 0.85 1.40
 High SES3 0.43 0.75 1.26 0.31 0.67 1.28 0.27 0.70 1.57
Percentage employed 1 month 6.25 4.92 2.91 7.20 3.96 1.91 9.81 5.18 2.24
Percentage employed 2 months 5.38 4.21 2.27 5.85 3.04 1.64 8.26 2.74 2.02
Percentage employed 3 months 3.99 2.60 2.09 5.30 2.75 1.66 7.73 3.35 1.89
Percentage employed 4 months 0.00 2.92 2.01 3.01 3.34 2.06 5.23 4.85 2.53
Percentage with 1 transition 7.06 4.94 2.84 7.34 3.98 2.05 9.69 4.89 2.47
Percentage with 2 transitions 6.99 4.98 2.80 6.91 3.08 1.77 9.33 4.65 1.98
Percentage with 3 transitions 0.00 2.77 1.32 3.01 1.25 0.57 6.27 1.07 0.46
1

This table presents standard errors corresponding to the percentages in table 2. The standard error for a given percentage 100p is calculated as sqrt{p*(1-p)/N}, where N is the sample size. The “average percentage employed each month” in table 2 is calculated as .25*(Percentage employed 1 month) + .5*(Percentage employed 2 months) + .75*(Percentage employed 3 months) + Percentage employed 4 months. Accordingly, the standard errors for this average are calculated as sqrt{.252*Var(Percentage employed 1 month) + .52*Var(Percentage employed 2 months) + .752*Var(Percentage employed 3 months) + Var(Percentage employed 4 months)}.

2

Children living in households with below-median adult household income.

3

Children living in households with above-median adult household income.