Table 1.
Mean Characteristics of the Two Groups in the Study
| Characteristic | Bilinguals (n = 40) | Monolinguals (n = 40) | t(78) | Cohen’s d |
|---|---|---|---|---|
| Age | 99 months (3.3) | 98 months (3.8) | 1.25 | 0.28 |
| Schooling | 54.9 months (4.6) | 54.6 months (8.4) | 0.20 | 0.04 |
| Number of students per class | 22.1 (9.8) | 22.4 (2.0) | −0.19 | 0.04 |
| Resident population | 9,741 (8,540) | 8,043 (15,461) | 0.61 | 0.14 |
| International Socio-Economic Index | 35.3 (6.2) | 35.7 (8.7) | −0.24 | 0.05 |
| BMI for age | 0.72 (1.1) | 0.81 (1.0) | −0.46 | 0.09 |
| Home stimulation | .71 (.15) | .70 (.16) | 0.23 | 0.06 |
| Caregiver education | 9.2 years (3.1) | 10.8 years (3.4) | −2.17* | 0.49* |
| Household possessions | .53 (.15) | .64 (.14) | −3.60* | 0.76* |
| Household size | 4.4 (0.90) | 3.8 (0.89) | 3.00* | 0.67* |
| Annual household income | $23,882 ($7,850)a | $11,095 ($6,076)b | — | — |
Note: Standard deviations are given in parentheses. The highest level of education of either caregiver was used to determine caregiver education and occupation. Body mass index (BMI; given as z scores) was established following guidelines of the World Health Organization (2008) with calibrated Plenna MEA 07400 scales (Plebal Plenna Balanças Comércio, São Paulo, Brazil), Seca 214 stadiometers (Seca GmbH & Co, Hamburg, Germany), and World Health Organization (2009) Anthroplus software. Home stimulation and household possessions are given in proportions; caregivers were asked a series of questions with rating-scale format, and responses were totaled and divided by the highest possible score. Annual household income represents the annual median equivalized disposable household income in U.S. dollars (Organisation for Economic Co-operation and Development, 2011). Data were obtained from caregivers and teachers using the Luxembourg Language and Background Questionnaire– Portuguese Version, the Luxembourg Teacher Questionnaire–Luxembourgish Version, and the Luxembourg Teacher Questionnaire–Portuguese Version, all of which were designed for this study.
$23,882 corresponds to 30% below the median annual household income in Luxembourg.
$11,095 corresponds to 15% below the median annual household income in Portugal.
p < .05.