Correlational finding on Happiness and Happiness of sibblings
Subject code: H08ac04

StudyLoehlin & Nichols (1976): study US 1963
TitleHeredity, Environment and Personality. A Study of 850 Sets of Twins.
SourceUniversity of Texas Press, 1976, Austin, USA
PublicAdolescent same-sex twins, USA, 1963
SampleProbability stratified sample
Non-Response29 %
Respondents N =850

Correlate
Author's labelHappiness of twin sibling
Page in Source 14
Our classificationHappiness of sibblings, code H08ac04
Operationalization
A Happiness of Identical twins
  a brothers
  b sisters
B Happiness of Fraternal twins
  a brothers
  b sisters
Observed distributionN for happiness = A: 486 Aa: 204, Ab: 282, B: 320 Ba: 130, Bb: 190 N for % cheerful & satisfied = A: 509, Aa: 216, Ab: 293, B: 330, Ba: 135, Bb: 195
Remarks
All twins are same sex

Observed Relation with Happiness
Happiness
Measure
StatisticsElaboration/Remarks
O-HP-g-sq-v-7-ar=+.37
Happiness of identical twins (average r)
- brothers r = +.41 
- sisters  r = +.34
O-HP-g-sq-v-7-ar=+.21
Happiness of fraternal twins (average r)
- brothers r = +.12
- sisters  r = +.27

Difference betwee correlations among identical & 
fraternal twins significant (p<05)
O-HP-g-sq-v-2-br=+.26
Happiness of identical twins (average r)
- brothers r = +.14 
- sisters  r = +.35
O-HP-g-sq-v-2-br=+.09
Happiness of Fraternal twins(average r)
- brothers r = +.17
- sisters  r = +.03)

Difference between correlations among identical & 
fraternal twins significant (p<.05)
O-HP-g-sq-v-2-cr=+.16
Happiness of identical twins
- brothers r = +.07 
- sisters  r = +.23
O-HP-g-sq-v-2-cr=+.07
Happiness of fraternal twins
- brothers r= +.11 
- sisters  r= +.05 

Difference between correlations among identical & 
fraternal twins ns

Significance tests computed by us, assuming that 
these samples are a probability sample of a wider 
population of twins.


Appendix 1: Happiness measures used
CodeFull Text
O-HP-g-sq-v-2-bSelfreport on single question:

Which of the following adjectives do you consider to be descriptive of yourself? Circle the number besides any adjective that you might use in describing yourself to someone else. Your behavior will vary with situation of course, so circle the numbers besides adjectives that apply to you frequently, even though they may not apply all the time. Work rapidly putting down your first thoughts.

Cheerful
1 no (not circled)
2 yes (circled)

Item in longer personality inventory
O-HP-g-sq-v-2-cSelfreport on single question:

Which of the following adjectives do you consider to be descriptive of yourself? Circle the number besides any adjective that you might use in describing yourself to someone else. Your behavior will vary with situation of course, so circle the numbers besides adjectives that apply to you frequently, even though they may not apply all the time. Work rapidly putting down your first thoughts.

Satisfied
1 no (not circled)
2 yes (circled)

Item in longer personality inventory
O-HP-g-sq-v-7-aSelfreport on single question:

Below are a number of dimensions on which people can vary. Please rate yourself on each dimension as honestly as you can. Many of the traits depend on the situation of course, but try to rate yourself as you usually are.

Happy-unhappy
7 very happy
6 fairly happy
5 slightly happy
4 neither or both
3 slightly unhappy
2 fairly unhappy
1 very unhappy

Item in longer personality inventory
Numbers reversed original presentation (happy 1, unhappy 7)


Appendix 2: Statistics used
SymbolExplanation
rPRODUCT-MOMENT CORRELATION COEFFICIENT (Also "Pearson's correlation coefficient' or simply 'correlation coefficient')
Type: test statistic.
Measurement level: Correlate: metric, Happiness: metric
Range: [-1; +1]

Meaning:
r = 0 no correlation ,
r = 1 perfect correlation, where high correlate values correspond with high happiness values, and
r = -1 perfect correlation, where high correlate values correspond with low happiness values.
Source:
Ruut Veenhoven, World Database of Happiness, Collection of Correlational Findings, Erasmus University Rotterdam.
https://worlddatabaseofhappiness.eur.nl