Table A2.
Summary Statistics for Differing Samples of Siblings
| Siblings Pairs with Data for:
|
||||
|---|---|---|---|---|
| IQ (1) | Birth Weight (2) | DNA (3) | BW + DNA (4) | |
| IQ | 101.35 (15.37) | 103.25 (14.85) | 104.56 (15.02) | 104.19 14.82 |
| Birth Weight (in grams) | 3394.96 (636.82) | 3367.55 (631.85) | ||
| Neuroplasticity Genes (Additive Score) | 4.39 (1.04) | 4.35 (1.06) | ||
| Mother’s Education | 10.52 (2.77) | 10.75 (2.67) | 10.68 (2.78) | 10.77 (2.78) |
| Father’s Education | 9.74 (3.35) | 9.98 (3.37) | 9.97 (3.35) | 10.17 (3.38) |
| Family SES in 1957 | 16.17 (10.93) | 16.82 (11.01) | 16.77 (11.26) | 17.52 (11.65) |
| Birth Year | 1939.29 (4.84) | 1939.69 (4.63) | 1939.49 (4.52) | 1939.66 (4.27) |
| Female | 0.52 (0.52) | 0.56 (0.50) | 0.52 (0.50) | 0.55 (0.50) |
| Birth Order | 2.54 (1.73) | 2.35 (1.48) | 2.50 (1.66) | 2.34 (1.42) |
|
| ||||
| N | 13224 | 2360 | 2246 | 938 |
Notes: Column (1) restricts the sample to sibling pairs containing data on IQ as well as our base set of controls. Column (2) gives sample statistics for sibling pairs containing data on birth weight, while column (3) restricts the sample to sibling pairs with data for our neuroplasticity SNPs. Column (4) restricts the sample to sibling pairs with both birth weight and DNA data; this represents our base sibling sample.