Table 2 Results of ANOVA and Kruskal–Wallis H tests between LBOTE and ELB groups
Variable | LBOTE | ELB | Statistic | p-value | ||
|---|---|---|---|---|---|---|
N | M (SD) | N | M (SD) | |||
(a) Academic outcome variables | ||||||
 Grade 3 NAPLAN reading scores | 137 | 449.28 (89.86) | 1379 | 446.71 (93.45) | 0.23b | 0.63 |
 Grade 3 NAPLAN writing scores | 137 | 442.38 (59.53) | 1372 | 426.30 (61.22) | 10.50b | < 0.01 |
 Years 3 NAPLAN spelling scores | 137 | 450.78 (91.44) | 1372 | 420.09 (77.15) | 19.56b | < 0.001 |
 Grade 3 NAPLAN grammar and punctuation scores | 137 | 461.09 (97.80) | 1372 | 446.30 (90.16) | 1.61b | 0.21 |
 Grade 3 NAPLAN numeracy scores | 135 | 424.48 (84.01) | 1376 | 415.24 (72.24) | 0.93b | 0.34 |
 Grade 5 NAPLAN reading scores | 113 | 523.74 (81.73) | 1257 | 529.52 (81.65) | 0.31b | 0.58 |
 Grade 5 NAPLAN writing scores | 112 | 492.97 (66.66) | 1249 | 482.38 (65.38) | 3.61b | 0.06 |
 Grade 5 NAPLAN spelling scores | 112 | 535.73 (76.60) | 1257 | 505.73 (71.96) | 14.28b | < 0.001 |
 Grade 5 NAPLAN grammar and punctuation scores | 112 | 540.00 (91.40) | 1257 | 528.35 (83.39) | 1.51b | 0.22 |
Variable | LBOTE | ELB | Statistic | p-value | ||
|---|---|---|---|---|---|---|
N | M (SD) | N | M (SD) | |||
(b) Demographic variables | ||||||
 Sex (male/female) | 215 | 1.53 (0.50) | 1790 | 1.50 (0.50) | 0.81a | 0.37 |
 Birth weight (grams) | 213 | 3399.42 (523.14) | 1780 | 3478.84 (539.92) | 5.65b | 0.02 |
 Combined family annual income $AUD * | 196 | 6.67 (2.93)* | 1691 | 5.53 (2.56)* | 26.22b | < 0.001 |
 Maternal education | 213 | 6.22 (1.78) | 1788 | 6.30 (1.49) | 0.01b | 0.93 |
 Breastfeeding duration (days) | 200 | 255.98 (202.93) | 1546 | 228.87 (203.93) | 4.60b | 0.03 |
 Age at Grade 3 NAPLAN test (months) | 141 | 101.77 (4.16) | 1429 | 102.68 (4.27) | 4.17b | 0.04 |
 Age at Grade 5 NAPLAN test (months) | 119 | 125.61 (3.90) | 1293 | 126.09 (3.57) | 1.34b | 0.25 |
Variable | LBOTE | ELB | Statistic | p-value | ||
|---|---|---|---|---|---|---|
N | M (SD) | N | M (SD) | |||
(c) Tobacco and alcohol use variables | ||||||
 Maternal average daily cigarettes smoked while pregnant | 143 | 0.14 (1.07) | 1523 | 0.66 (2.65) | 9.29b | < 0.01 |
 Maternal average daily cigarettes smoked while breastfeeding | 165 | 0.45 (2.02) | 1590 | 1.06 (3.79) | 2.87b | 0.09 |
 Days per week mother drank alcohol during 1st trimester of pregnancy | 150 | 0.06 (0.35) | 1584 | 0.18 (0.74) | 5.13b | 0.02 |
 Days per week mother drank alcohol during 2nd trimester of pregnancy | 150 | 0.04 (0.26) | 1582 | 0.22 (0.76) | 10.25b | < 0.01 |
 Days per week mother drank alcohol during 3rd trimester of pregnancy | 150 | 0.05 (0.28) | 1581 | 0.25 (0.87) | 8.02b | 0.01 |
 Average number of alcoholic drinks mother consumed on each drinking occasion during pregnancy | 150 | 0.19 (0.41) | 1579 | 0.48 (0.54) | 41.47b | < 0.001 |
 Maternal alcohol consumed while breastfeeding | 151 | 3.09 (2.48) | 1338 | 5.83 (2.29) | 126.69b | <0.001 |
Variable | LBOTE | ELB | Statistic | p-value | ||
|---|---|---|---|---|---|---|
N | M (SD) | N | M (SD) | |||
(d) Homework and tutoring variables | ||||||
 Homework frequency (Wave 4) | 178 | 1.38 (0.74) | 1392 | 1.39 (0.64) | 0.36b | 0.55 |
 Homework help (Wave 4) | 178 | 1.45 (0.74) | 1392 | 1.44 (0.71) | 0.04b | 0.84 |
 Tutoring (Wave 4) | 178 | 1.88 (0.32) | 1389 | 1.89 (0.31) | 0.14a | 0.71 |
 Tutoring frequency (Wave 4) | 20 | 1.70 (0.57) | 151 | 1.81 (0.68) | 0.33b | 0.57 |
 Homework hours (Wave 5) | 164 | 2.70 (2.11) | 1333 | 2.48 (1.80) | 0.82b | 0.37 |
 Homework help (Wave 5) | 164 | 2.25 (1.04) | 1333 | 2.12 (0.99) | 2.40b | 0.12 |
 Tutoring (Wave 5) | 168 | 1.89 (0.32) | 1387 | 1.84 (0.37) | 2.46a | 0.12 |
 Tutoring frequency (Wave 5) | 19 | 1.63 (0.50) | 219 | 1.85 (0.63) | 2.05b | 0.15 |
 Homework hours (Wave 6) | 146 | 2.77 (1.99) | 1164 | 2.74 (1.90) | < 0.001b | 0.99 |
 Homework help (Wave 6) | 146 | 2.47 (1.03) | 1164 | 2.64 (1.01) | 4.23b | 0.04 |
 Tutoring (Wave 6) | 153 | 1.79 (0.41) | 1239 | 1.84 (0.37) | 1.92a | 0.17 |
 Tutoring frequency (Wave 6) | 32 | 1.88 (0.55) | 203 | 1.87 (0.57) | 0.01b | 0.93 |