Correlational finding on Happiness and subject: Breakfast (or not)

StudyOECD (2017): study TR 2015
TitlePISA 2015 Results. Students' Well-Being. Volume III.
SourceOECD Publishing, 2017, Paris, France
URLhttp://www.oecd-ilibrary.org/education/pisa-2015-results-volume-iii_9789264273856-en
Public15-16 aged, secundary school students, Turkey, 2017
SampleProbability multi-stage random
Non-Response
Respondents N =5895

Correlate
Author's labelEating habits
Page in Source Table III.11.27, p.458
Our classificationBreakfast (or not)
Operationalization
Selfreport on 2 questions:
- On the most recent day you attended school, did you 
before going  to school eat breakfast? 
     1 yes
     0 no
- On the most recent day you attended school, did you 
after leaving school eat diner?
     1 yes
     0 no

Observed Relation with Happiness
Happiness
Measure
StatisticsElaboration/Remarks
C-BW-c-sq-l-11-eDM=+
breakfast      all         boys       girls
yes:       M=  6,39        6,66       6,10
no:        M=  5,09        5,14       5,06
- difference: +1,50(.05)  +1,51(ns)  +1,04(.05)

Difference slightly smaller after control for 
student's socio-economic status
C-BW-c-sq-l-11-eDM=+
dinner         all         boys       girls  
yes:       M=  6,14        6,43       5,87
no:        M=  5,35        5,88       4,83
- difference: +0,79(.05)  +0,55(ns)  +1,03(.05)

Difference slightly smaller after control for 
student's socio-economic status


Appendix 1: Happiness measures used
CodeFull Text
C-BW-c-sq-l-11-eSelfreport on single question:

Here is a picture of a ladder. The top of the ladder '10' represents the best possible life for you and the bottom '0' is the worst possible life for you. In general , where on the ladder do you feel you stand at the moment? Tick the box next to the number that best describes where you stand
10 best possible
9
8
7
6
5
4
3
2
1
0 worst possible life


Appendix 2: Statistics used
SymbolExplanation
DMDIFFERENCE of MEANS
Type: descriptive statistic only.
Measurement level: Correlate: dichotomous, Happiness: metric
Range: depending on the happiness rating scale of the author; range symmetric about zero.

Meaning: the difference of the mean happiness, as measured on the author's rating scale, between the two correlate levels.
Source:
Ruut Veenhoven, World Database of Happiness, Collection of Correlational Findings, Erasmus University Rotterdam.
https://worlddatabaseofhappiness.eur.nl