Table A1.
Summary Statistics for Differing Samples
| Base Sibling (Unweighted) (1) | Base Sibling (Weighted) (2) | All with DNA and Birth Weight (3) | All with DNA (4) | All with Birth Weight (5) | Max (6) | |
|---|---|---|---|---|---|---|
| IQ | 104.19 (14.82) | 101.43 (14.67) | 103.73 (14.80) | 103.46 (14.95) | 102.61 (14.85) | 101.38 (15.27) |
| Mother’s Education | 10.77 (2.78) | 10.67 (2.77) | 10.70 (2.76) | 10.62 (2.80) | 10.63 (2.74) | 10.51 (2.79) |
| Father’s Education | 10.17 (3.38) | 10.03 (3.36) | 9.97 (3.41) | 9.88 (3.42) | 9.87 (3.39) | 9.76 (3.41) |
| Family SES in 1957 | 17.52 (11.65) | 16.96 (11.45) | 17.01 (11.08) | 16.75 (11.10) | 16.75 (11.03) | 16.40 (11.03) |
| Birth Year | 1939.66 (4.27) | 1939.24 (3.75) | 1939.31 (3.57) | 1939.21 (3.65) | 1939.34 (3.72) | 1939.24 (4.39) |
| Female | 0.55 (0.50) | 0.51 (0.50) | 0.56 (0.50) | 0.52 (0.50) | 0.58 (0.50) | 0.52 (0.50) |
| Birth Order | 2.34 (1.42) | 2.30 (1.40) | 2.36 (1.67) | 2.47 (1.78) | 2.38 (1.68) | 2.51 (1.80) |
| Birth Weight (in grams) | 3367.55 (631.85) | 3363.75 (635.38) | 3378.36 (630.02) | – – |
3374.32 (636.72) | – – |
| Neuroplasticity Genes (Additive Score) | 4.35 (1.06) | 4.35 (1.06) | 4.39 (1.04) | 4.40 (1.03) | – – |
– – |
|
| ||||||
| N | 938 | 938 | 3799 | 6097 | 6452 | 15676 |
Notes: Columns (1) and (2) are comprised of our base sibling pair sample. Column (3) consists of all individuals (i.e., not pairs) that contain data for the SNPs used to measure neuroplasticity and birth weight. Column (4) consists of all individuals with data for neuroplasticity SNPs and column (5) consists of all individuals with data for birth weight. Column (6) gives sample statistics for the maximum available sample. SES is an index created from father’s education, mother’s education, father’s occupation (Duncan SEI), and family income.