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Table 1 Socio-demographic and exposure characteristics of the analytic samples

From: Backyard benefits? A cross-sectional study of yard size and greenness and children’s physical activity and outdoor play

  Sample 1 (n = 1648) Sample 2 (n = 391)
Variable Mean (SD) or % Mean (SD) or %
Age of child (years) 6.3 (0.4) 6.2 (0.4)
Sex, %
 Male 50.3 50.6
 Female 49.3 48.3
 Missing 0.4 1.0
Mother’s ethnicity, %
 Caucasian 77.3 79.0
 Asian 14.4 12.8
 Middle Eastern 1.3 1.3
 Other1 3.9 5.1c
 Missing 3.0 1.8
Mother’s education, %
 Up to Year 12 11.8 13.3
 Trade, Apprenticeship and other 20.3 23.3
 Bachelor degree or higher 63.7 61.1
 Other 0.7 0.0
 Missing 3.4 2.3
Neighbourhood SES (IRSD score)3 1046.5 (50.3) 1050.8 (49.0)
Presence of Siblings, %
 Yes, and siblings live at home2 89.1 91.6
 No siblings, or siblings not at home 8.5 7.4
 Missing 2.4 1.0
Presence of dogs, %
 Have a dog 32.1 33.5
 No dog 65.1 65.0
 Missing 2.8 1.5
Yard Size
 Median (Inter Quartile Range), m2 374.4 (249.6–506.4) 357.4 (261.1–481.9)
 % over 50m2 97.3 98.0
 Greenness (rescaled NDVI), median (SD)4 3.9 (1.1) 4.0 (1.0)
  1. Due to rounding percentages may not add to 100%
  2. IRSD index of relative socioeconomic disadvantage, NDVI normalised difference vegetation index, SD standard deviation, SES socioeconomic status
  3. 1 Other includes those who noted their ethnicity as African, Aboriginal and Torres Strait Islander, as of a mixed ethnicity, or another ethnicity that was not listed as an option on the questionnaire
  4. 2 Living at home was defined as living at home for more than 50% of the week
  5. 3 IRSD score: national mean 1000 (SD: 100). A low IRSD score indicates relatively greater disadvantage and a high IRSD score indicates a relative lack of disadvantage
  6. 4 rescaled NDVI, a scale from 0 to 10 with 0 representing no vegetation and 10 representing full, healthy vegetation