Table 4.
Mx Model Fitting Estimates for Learning and Literacy Measures (95% Confidence Intervals in Parentheses).
| Variable | a2 | c2 | e2 |
|---|---|---|---|
| WRAML Story Memory | ..40 (.21–.54) | .07 (.00–.24) | .54 (.46–.59) |
| WRAML Sound-symbol | .27 (.04–37) | .04 (.00–.22) | .70 (.63–.77) |
| Nonword repetition | .45 (.27–.61) | .12 (.00–.27) | .43 (.38–.49) |
| WPPSI Sentence memory | .49 (.35–.63) | .23 (.09–.35) | .28 (.25–.33) |
| Hundred Pictures | .23 (.12–.34) | .52 (.42–.61) | .25 (.22–.29) |
| WPPSI Vocabulary | .16 (.01–.31) | .42 (.29–.54) | .42 (.37–.47) |
| Boston naming | .45 (.34–.57) | .37 (.25–.57) | .19 (.16–.22) |
| Letter knowledge | .18 (.09–.28) | .58 (.49–.66) | .23 (.20–.27) |
| Orthographic learning | .58 (.39–.66) | .03 (.00–.20) | .39 (.34–.45) |
| TOWRE SWE | .83 (.70–.85) | .00 (.00–.13) | .17 (.15–.20) |
| TOWRE PDE | .81 (.67–.85) | .01 (.00–.14) | .18 (.15–.21) |
Note. WRAML = Wide Range Assessment of Memory and Learning; TOWRE SWE= Test of Word Reading Efficiency, Sight Word Efficiency; TOWRE PDE= Test of Word Reading Efficiency, Phonemic Decoding Efficiency; WPPSI =Wechsler Preschool and Primary Scale of Intelligence; a2 = additive genetic variance, c2 = shared environment variance, e2 = nonshared environment variance. Estimates with confidence intervals including .00 are not significantly greater than 0.