Table 2.
Descriptive statistics collected at age 13 years (N = 401)
| Boys | Girls | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| n | M | SD | 95 % CI | Range | n | M | SD | 95 % CI | Range | |
| Same-sex romantic attractions | 197 | 0.04 | 0.23 | 0.02, 0.08a | 0 to 2.71 | 195 | 0.06 | 0.20 | 0.03, 0.09a | 0 to 1.14 |
| Other-sex romantic attractions | 197 | 1.71 | 0.99 | 1.57, 1.85 | 0 to 4 | 195 | 1.40 | 0.91 | 1.27, 1.53 | 0 to 4 |
| Heterosexual expectations | 194 | 3.12 | 0.65 | 3.03, 3.22 | 1 to 4 | 187 | 3.11 | 0.66 | 3.02, 3.21 | 1 to 4 |
| Other-sex sexual activities | 204 | 0.07 | 0.94 | −0.06, 0.20 | −1.08 to 2.62b | 197 | 0.01 | 0.90 | 0.12, 0.13 | −1.08 to 2.62b |
| Pubic hair development | 186 | 3.35 | 0.97 | 3.21, 3.50 | 1 to 5 | 186 | 3.83 | 0.84 | 3.71, 3.95 | 1 to 5 |
| Physical development | 185 | 3.61 | 0.96 | 3.47, 3.74 | 2 to 5 | 188 | 3.49 | 0.87 | 3.36, 3.62 | 1 to 5 |
Note A higher value of a variable represents a larger extent or a higher level of that variable. Overlapping CIs between the sexes indicate significant sex differences at α = .05, two-tailed
aBootstrapped 95 % CI is reported
bIRT scores as generally used are standardized so that they can vary from −∞ to +∞, although in practical this range changes depending on item difficulty in a particular scale (how many participants scored 0 versus 1 on an item) (Embretson & Reise, 2000). These scores can be used to infer the probability of a participant engaging in a given sexual activity (cf. Fig. A, upper panel)