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Correlational findings

Study Plomin et al. (1993): study US Colorado 1986

Public:
Same-sex twins, Colorado, United States, followed from 14 to 20 months, 1986-1989
Sample:
Respondents:
N = 398
Non Response:
Assessment:
Behavioural observation
At 14 months: observation at home, 2 weeks later observation in laboratory

Correlate

Authors's label
Happiness of twin siblings
Our Classification
Operationalization
at 14 and 20 months, twin pairs were first observed at home and 1-3 weeks after that in the laboratory at the Institute for Behavioral Genetics in Boulder during different situations, behavior was videotaped and rated afterwards; the mother was interviewed via phone between the home & lab sessions;

Observed Relation with Happiness

Happiness Measure Statistics Elaboration / Remarks A-CA-mi-tsb-v-7-a = SAME TIME CORRELATION A-CA-mi-tsb-v-7-a r = +.19 p < .05 Monozygotic twins at 14 months A-CA-mi-tsb-v-7-a r = +.02 ns Dizygotic twins at 14 months A-CA-mi-tsb-v-7-a r = +.27 p < .05 Monozygotic twins at 20 months A-CA-mi-tsb-v-7-a r = +.21 p < .05 Dizygotic twins at 20 months A-CA-mi-tsb-v-7-a = Heritability component in this correlation:
- at 14 months h²=+.15 (ns)
- at 20 months h²=+.10 (ns)
A-CA-mi-tsb-v-7-a = Shared Environment component in this correlation:
- at 14 months c²=+.00 (ns)
- at 20 months c²=+.17 (ns)
A-CA-mi-tsb-v-7-a = CORRELATION OF CHANGE:
Twin correlations based on each individual's relative change score (20 months - 14 months) using a double entry file.
A-CA-mi-tsb-v-7-a r = +.03 ns Monozygotic twins A-CA-mi-tsb-v-7-a r = +.01 ns Dizygotic twins A-CA-mi-tsb-v-7-a = Heritability component:       h²=+.03 (ns)
Shared Environment component: c²=+.00 (ns)
A-CA-mi-tsb-v-7-a = CORRELATION OF CONTINUITY:
The analysis of continuity is based on cross-twin correlations, that is, the correlation between one twin's score at 14 months and the co-tin's score at 20 months using a double-entry file.
A-CA-mi-tsb-v-7-a r = +.21 p < .05 Monozygotic twins A-CA-mi-tsb-v-7-a r = +.09 ns Dizygotic twins A-CA-mi-tsb-v-7-a = Heritability component:       h²=+.21 (05)
Shared Environment component: c²=+.00 (ns)
A-CA-mi-tsb-v-7-a =