Muhammad Ichsan Fadillah
Poznań Uni e si y o Li e Sciences
ul. Wojska Polskiego 28 Poznań 60-624 Poland
e-mail: [email p o ec ed]
Jou nal o Li e and Medical Sciences
Niniejsze badanie analizuje złożone elacje między dochodem, szczęściem a bezpie-
czeńs wem żywnościowym w 99 k ajach w la ach 2012-2022. Wyko zys ując dane z Banku
Świa owego (GNI na mieszkańca sko ygowane o pa y e siły nabywczej), Wo ld Happiness
Repo o az Globalnego Indeksu Bezpieczeńs wa Żywnościowego The Economis , es ujemy, czy
ko elacje dochód-bezpieczeńs wo żywnościowe mają cha ak e wielomianowy, podczas gdy
elacje szczęście-bezpieczeńs wo żywnościowe pozos ają liniowe. Py anie badawcze b zmi: „Jak
wzajemnie oddziałują na siebie dochód, szczęście i bezpieczeńs wo żywnościowe na poziomie
globalnym?” Pop zez modele eg esji i es y ANOVA s osujemy eo ię malejącej uży eczności
k ańcowej o az koncepcje dob os anu subiek ywnego. Wyniki po wie dzają, że chociaż obecne
in e wencje ekonomiczne w k ajach o niskich dochodach pozos ają is o ne, sku eczne globalne
bezpieczeńs wo żywnościowe wymaga z ównoważonych podejść łączących ozwój gospoda -
czy z pop awą dob os anu, szczególnie w k ajach o wysokich dochodach.
N 1/39/2025 I Nauki P zy odnicze i Medyczne
S eszczenie
3
Słowa kluczowe: dochód, szczęście, bezpieczeńs wo żywnościowe, analiza globalna,
wpływy społeczne.
This s udy examines he complex ela ionships be ween income, happiness, and ood secu i y
ac oss 99 coun ies du ing 2012-2022. Using da a om he Wo ld Bank (GNI pe capi a PPP-
adjus ed), Wo ld Happiness Repo , and he Economis ’s Global Food Secu i y Index, we es
whe he income- ood secu i y co ela ions ollow polynomial pa e ns while happiness- ood
secu i y ela ionships emain linea . The esea ch ques ion guiding his analysis is: “How do
income, happiness, and ood secu i y in e ela e a he global le el?” Th ough eg ession models
and ANOVA es ing, we apply diminishing ma ginal u ili y heo y and subjec i e well-being
amewo ks. Resul s con i m ha while cu en economic in e en ions a ge ing low-income
coun ies emain essen ial, e ec i e global ood secu i y equi es balanced app oaches inco -
po a ing bo h economic de elopmen and well-being enhancemen , pa icula ly in high-income
na ions.
Abs ac
Key wo ds: income, happiness, ood secu i y, global analysis, socie al impac s.
Explo ing he Nexus o Income, Happiness, and Food
Secu i y: A Global Analysis Ac oss 99 Coun ies
Badanie złożonych elacji między dochodem, szczęściem
a bezpieczeńs wem żywnościowym: Globalna analiza 99 k ajów
4
N 1/39/2025 I Nauki P zy odnicze i Medyczne
www.naukowcy.o g.pl
Nauki P zy odnicze i Medyczne
In oduc ion
A he end o 2023, he Wo ld Bank announced ha i has mobilized 45 billion dolla s o add ess-
ing ood secu i y p oblems, which su passed he ini ial commi men o 30 billion dolla s i has made in 2022
(Wo ld Bank, 2023). This e o was unde aken as ood insecu i y is escala ing, h ea ening ulne able com-
muni ies globally (Wo ld Bank, 2023). An es ima ed qua e o billion people ace acu e ood insecu i y, a ig-
u e ha ep esen s mo e han 33 pe cen yea -o e -yea inc ease (Wo ld Bank, 2023). I his end con inues,
he wo ld will hos 950 million ood-insecu e people in 2030 (Wo ld Bank, 2023). The Wo ld Bank’s inancial
commi men o ackle his p oblem is essen ial because i ep esen s a o m o ac ion ha can immedia ely ad-
d ess he ood secu i y eme gencies he wo ld is acing (Wo ld Bank, 2023).
The p oblems su ounding ood insecu i y a e mul i-causal (And ee e al., 2024). Two no able causes
o ood insecu i y a e he slow global eco e y om COVID-19; and Russia’s in asion o Uk aine. Bo h
e en s ha e impac ed economic s abili y by c ea ing ele a ed in la ion, igh e mone a y policies, and educed
inancial suppo (And ee e al., 2024). Beyond economic impac s, ood secu i y aces di ec h ea s om non-
enewed Black Sea G ain Ini ia i e and es ic i e ood ade policies ac oss di e en coun ies (Wo ld Bank,
2023). Addi ionally, he e is a h ea caused by El Nino clima e pa e n (Wo ld Bank, 2023).
The causes o ood insecu i y conc e ely esul in he de ailmen o he 2nd goal o Sus ainable De el-
opmen Goals (SDG) which is ze o hunge by 2030, also known as SDG2 (And ee e al., 2024). The ac ha
ood secu i y is speci ically add essed as one o he 17 goals in SDG sugges s a need o e o ha is wo ld-
wide in scale o add ess he issue (Uni ed Na ions, 2024). The posi ion o ze o hunge as goal numbe 2 in he
SDG lis is indica i e o no only i s impo ance in e ms o p io i y, bu also in e ms o i s ole being he base
o o he goals (Uni ed Na ions, 2024).
SDGs sugges ha he goals o economic ac i i ies should ocus on no only g ow h bu also sus ain-
abili y, because h ough sus ainabili y, economic success will be achie ed no only o oday bu also o he
u u e (Singh Toma , 2023). Wi h he slogan o “lea ing no one behind”, SDGs imply ha economic bene i s
should co e e e yone (Sus ainabili y Knowledge G oup, 2021). Since SDGs’ mission is o imp o e he li es
o all people, SDGs a e closely ela ed o happiness (Sus ainabili y Knowledge G oup, 2021). The Wo ld
Happiness Repo (WHR), he i s o i s kind o epo coun ies based on hei happiness a he han adi-
ional economic measu emen s like GDP, sugges s ha SDG index and subjec i e well-being (SWB) ha e a
quad a ic ela ionship, indica ing ha a highe SDG sco e co ela es mo e s ongly wi h highe SWB a highe
le els o he SDG index (De Ne e and Sachs, 2020).
The use o happiness as a measu emen o coun ies was pionee ed by Bhu an wi h i s G oss Na ional
Happiness (GNH) (Boy eau, 2016). In he 1970s, Bhu an’s king men ioned ha GNH is mo e impo an han
GDP (Boy eau, 2016). While some iew GNH as a ou ism ma ke ing s a egy, he use o GNH has b ough
eal bene i s o po e y alle ia ion and sha ed p ospe i y in he coun y (Boy eau, 2016). Fu he mo e, i ini i-
a ed he philosophical ques ion among economis s o whe he coun ies should pace he economic p og ess
o allow all non-mone a y dimensions o de elopmen , like cul u e and social ela ions, o ca ch up (Boy eau,
2016).
The GNH philosophy consis s o ou pilla s, one o which is sus ainable de elopmen (Boy eau,
2016). Since ood secu i y is an impo an pa o sus ainable de elopmen as seen om SDG2, he linkage
be ween happiness and sus ainable de elopmen implies he adop ion o bo h happiness and ood secu i y in o
he economic ealm. This is he cen al heme o his pape . Focusing on he happiness-economy- ood secu i y
nexus, his pape seeks o in es iga e he co ela ion be ween income, ood secu i y index, and happiness in-
dex.
This analysis is pa icula ly ele an in e ms o he na u e o he cu en app oach o ood secu i y
globally. The Wo ld Bank’s p ojec announced in May 2022 ocuses on he inancial aspec o app oach ood
secu i y issues (Wo ld Bank, 2022a). Fu he mo e, e o s o achie e global ood secu i y e ol e a ound
p oblems aced by de eloping coun ies, like ex eme po e y (Uni ed Na ions Gene al Assembly, 2023). By
analyzing da a om 99 coun ies wi h a ious income le els, his pape aims o p o ide empi ical e idence
as o whe he he ocus on economic in e en ions in low-income coun ies e ec i ely add esses global ood
secu i y challenges.
Jou nal o Li e and Medical Sciences
N 1/39/2025 I Nauki P zy odnicze i Medyczne
5
www.naukowcy.o g.pl
Cu en s a e o knowledge
Pas esea ch has ocused on income, happiness, and ood secu i y. One s udy su eyed da a om
low-income households in A lan a, Geo gia, US in 2004 (Bezuneh and Yiheyis, 2020). Se e al indings o he
s udy include: (1)low-income households, e en hose classi ied as ood secu e, gene ally s uggle o co e
hei mon hly expenses and o en eso o a ious coping s a egies like delaying non- ood pu chases and
bo owing om iends and amily o make ends mee , (2) he e is a signi ican misma ch be ween household
sel -assessmen o hei ood condi ions and he s anda d ood-secu i y classi ica ion, indica ing ha many
households eel mo e ood secu e han hey ac ually a e acco ding o o icial measu es, and (3)despi e ecei -
ing go e nmen assis ance, a subs an ial pe cen age o low-income households emain ood insecu e, sugges -
ing he assis ance may be inadequa e o ine ec i e (Bezuneh and Yiheyis, 2020).
The s udy employed desc ip i e and co ela ion analyses o examine he ela ionships be ween income
s a us, ood secu i y sel -assessmen , and happiness (Bezuneh and Yiheyis, 2020). Fou heo e ical ame-
wo ks guided he analysis (Bezuneh and Yiheyis, 2020). These include Ama ya Sen’s capabili y app oach,
Richa d Laya d’s happiness economics, Maxwell and Smi h’s coping s a egies amewo k, and USDA’s ood
secu i y measu emen (Bezuneh and Yiheyis, 2020).
Ano he s udy examined he ela ionship be ween ood secu i y and happiness using he da a om 105
coun ies om 2012 o 2019 (Salahodjae and Mi ziyoye a, 2021). The s udy used he happiness da a om
WHR and ood insecu i y om he Global Food Secu i y Index (GFSI) om he Economis (Salahodjae and
Mi ziyoye a, 2021). The esea che s conduc ed a bi a ia e eg ession analysis, speci ically O dina y Leas
Squa es (OLS) me hod, o examine he co ela ion be ween he wo, while adjus ing o GDP g ow h, go e n-
men size, democ acy s a us, gende equali y, co up ion le el, as well as social kindness (Salahodjae and
Mi ziyoye a, 2021).
The s udy’s indings include a signi ican nega i e co ela ion be ween li e sa is ac ion and ood in-
secu i y (Salahodjae and Mi ziyoye a, 2021). Speci ically, one uni o inc ease in ood insecu i y dec eases
li e sa is ac ion by 0.8 uni s (Salahodjae and Mi ziyoye a, 2021). Fu he mo e, he ela ionship emained
consis en and s ong a e all adjus men ac o s we e in oduced (Salahodjae and Mi ziyoye a, 2021).
While he s udy did no explici ly e e ence heo e ical amewo ks, se e al guiding concep s in o med
he analysis (Salahodjae and Mi ziyoye a, 2021). These concep s include human capi al, ins umen al a i-
able app oach, and con ol a iables (Salahodjae and Mi ziyoye a, 2021).
Ano he pape ha in es iga es he co ela ion be ween happiness and ood secu i y speci ically s ud-
ied Chinese a me s (Zhu and Leng, 2023). The s udy u ilized he da a published by he China Social Su ey
(CSS) in 2013 as he p ima y e e ence, while 2017 and 2021 we e used as compa ison poin s (Zhu and Leng,
2023). The esea che s employed a leas i e s a is ical me hods including P opensi y Sco e Ma ching me h-
od, Recu si e Bi a ia e O de ed P obi model, Condi ional Mixed P ocess me hod, O dina y Leas Squa es
and O de ed P obi eg ession models, as well as In e se P obabili y Weigh ing (IPW) and IPW-Reg ession
Adjus men (Zhu and Leng, 2023).
The heo e ical ounda ion spans om classical o con empo a y economic heo ies o happiness (Zhu
and Leng, 2023). The amewo k inco po a es A is o elian concep s o happiness, Adam Smi h’s weal h-sa is-
ac ion ela ionship, Wel a e Economics’ u ili y maximiza ion, and Eas e lin’s pa adox ega ding he complex
income-happiness ela ionship (Zhu and Leng, 2023).
The s udy ound ha Chinese a me s’ pe cep ion o ood sa e y has a signi ican posi i e impac on
hei happiness (Zhu and Leng, 2023). Fu he mo e, he posi i e e ec o ood sa e y pe cep ion on happiness
is mo e p onounced among middle-aged, elde ly, and highly educa ed a me s, indica ing ha hese g oups a e
mo e sensi i e o ood sa e y issues (Zhu and Leng, 2023). The s udy se es as a policy ecommenda ion o
policymake s o ocus on imp o ing ood sa e y in u al a eas, p omo e ood sa e y awa eness, and educa e
a me s in ood sa e y supe ision o enhance o e all happiness among a me s (Zhu and Leng, 2023).
Ano he s udy ha examines he ela ionship be ween ood secu i y and happiness u ilizing p ima y
da a by conduc ing own su eys o olde people (60 yea s and up) in Thailand (Phulke d e al., 2023). The
s udy ound ha happiness among olde people is in luenced by a ious ac o s including ood- ela ed be-
ha io s, socio-demog aphic cha ac e is ics, and economic condi ions (Phulke d e al., 2023). The esea che s
in eg a ed hei indings wi h he Wo ld Heal h O ganiza ion (WHO) amewo k on heal h, pa icipa ion, and
6
N 1/39/2025 I Nauki P zy odnicze i Medyczne
www.naukowcy.o g.pl
Nauki P zy odnicze i Medyczne
Theo e ical amewo k
This pape employs he u ili y heo y o examine he ela ionship be ween income and ood secu i y,
pa icula ly he concep o diminishing ma ginal u ili y o income. Meanwhile, o unde s and he co ela ion
be ween happiness and ood secu i y, he heo y applied is he subjec i e well-being heo y, especially aspec s
ela ed o consump ion and li e sa is ac ion.
U ili y heo y pu s he ocus on u ili y when looking a income (Laya d e al., 2008). U ili y is a con-
cep in economics ha measu es sa is ac ion de i ed om goods and se ices (Laya d e al., 2008). The e o e,
while u ili y is usually associa ed o happiness, i can also be applied o a ious aspec s o li e, such as heal h,
educa ion, and ood secu i y (Laya d e al., 2008). The heo y s a es ha ex a sa is ac ion gained om income
dec eases as income inc eases (Laya d e al., 2008). A s udy ha analyzed he da a ac oss mul iple su eys
om 50 coun ies be ween 1972 and 2005, i inds ha he elas ici y o ma ginal u ili y om income anges
om 1.19 o 1.34, wi h a combined es ima e o 1.26 (Laya d e al., 2008). E en a e accoun ing o bias in
sa is ac ion epo ing, he e is only a sligh dec ease o his numbe , esul ing in 1.24 (Laya d e al., 2008). This
means ha no only does addi ional sa is ac ion om addi ional income dec eases, bu i does so a a simila
a e ac oss di e en popula ions (Laya d e al., 2008). This is called he diminishing ma ginal u ili y o income
(Laya d e al., 2008).
The diminishing ma ginal u ili y o income means ha he ma ginal inc ease in u ili y diminishes
as ma ginal income inc eases (Laya d e al., 2008). This esul s in a cu e ha ep esen s he ela ionship
be ween income and u ili y ha ing a downwa d slope (Laya d e al., 2008). Fo income-consump ion ela-
ionships, he cu e is loga i hmic (Laya d e al., 2008). This is because as income inc eases, he addi ional
sa is ac ion om each ex a uni o income dec eases a a dec easing a e, o ming a cu e ha la ens ou as
income g ows (Laya d e al., 2008). Bo h he downwa d slope in income-u ili y cu es and he loga i hmic
cu e in income-consump ion cu es sugges s ha he e is a consis en decline in u ili y as income inc eases
(Laya d e al., 2008).
I applied o ood secu i y, he diminishing ma ginal u ili y o income can conside ood secu i y as a
o m o consump ion. In his case, he e should be a loga i hmic cu e in he ela ionship be ween income and
ood secu i y. Con e sely, he co ela ion be ween happiness and ood secu i y is expec ed o be linea , which
is explained h ough he subjec i e well-being heo y.
The linea co ela ion be ween happiness and consump ion is de i ed om he subjec i e well-being
heo y whe e consump ion can be ansla ed in o happiness: h ough h ee key mechanisms: (1) p e e ence,
(2) au onomy, and (3) pe spec i e le el (Iye and Muncy, 2016). Rega ding p e e ence, inc ease in consump-
ion co ela es wi h inc ease in happiness only i i is in line wi h he pe sonal p e e ence o an indi idual (Iye
and Muncy, 2016). Fo au onomy, inc ease in consump ion co esponds o inc ease in happiness only i i os-
e s he sense o con ol ha one has o e hemsel es (Iye and Muncy, 2016). Conce ning pe spec i e le el,
consump ion and happiness can be iewed h ough wo di e en pe spec i es: pe sonal and socie al (Iye and
Muncy, 2016). The inc ease in consump ion co ela es wi h inc ease in happiness p ima ily a he pe sonal
le el (Iye and Muncy, 2016).
Simila o he posi i e ela ionship, dec eases in consump ion co espond o dec ease in happiness
(Iye and Muncy, 2016). Fo p e e ence, i a consump ion is agains one’s pe sonal p e e ence, hei happiness
will dec ease (Iye and Muncy, 2016). Rega ding au onomy, happiness dec eases when one’s consump ion
o goods is ou side o hei con ol (Iye and Muncy, 2016). Finally, conce ning pe spec i e le el, happiness
dec eases when consump ion is dic a ed by socie al condi ions (Iye and Muncy, 2016).
This pape employs h ee a iables: income, happiness, and ood secu i y. The s udy in es iga es wo
co ela ions: (1) be ween income and ood secu i y, and (2) be ween happiness and ood secu i y. The e o e,
he esea ch ques ion is “Wha is he ela ionship be ween income, ood secu i y, and happiness?”. This leads
o wo hypo heses: (1) he e is a posi i e loga i hmic co ela ion be ween income and ood secu i y, and (2)
secu i y as a basis o emphasize he impo ance o “ac i e ageing” (Phulke d e al., 2023).
The s udy employed mul i a ia e eg ession analysis (Phulke d e al., 2023). Addi ionally, he esea ch-
e s u ilized a supplemen a y da a using he Food Insecu i y Expe ience Scale (FIES) o assess ood secu i y
(Phulke d e al., 2023). The heo e ical amewo ks included subjec i e well-being and psychosocial well-be-
ing (Phulke d e al., 2023).
Jou nal o Li e and Medical Sciences
N 1/39/2025 I Nauki P zy odnicze i Medyczne
7
www.naukowcy.o g.pl
is a posi i e linea co ela ion be ween happiness and ood secu i y.
Da a and me hodology
The a iables a e aken om di e en sou ces. Fo income, he da ase is om he Wo ld Bank, espe-
cially he GNI pe capi a, PPP-adjus ed (Wo ld Bank, 2024). Fo happiness, he da ase used in his pape is
aken om he Wo ld Happiness Repo (WHR) (Wo ld Happiness Repo , 2024). Finally, o ood secu i y,
he da a used is he Global Food Secu i y Index (GFSI) aken om he Economis (The Economis , 2022a).
The sample consis s o 99 coun ies o 10 yea s om 2012 o 2022.
GFSI is an annual epo on global ood secu i y published by a body unde he Economis called he
Economis Impac (The Economis , 2022a). The Economis Impac i sel is desc ibed as combining “ he igo
o a hink- ank wi h he c ea i i y o a media b and o engage a globally in luen ial audience” (The Economis ,
2022b). I wo ks in coope a ion wi h Co e a Ag iscience, which is a global ag icul u e company ocused on
deli e ing solu ions o ag icul u al challenges (The Economis , 2022b). The Index conside s he ac o s o a -
o dabili y, a ailabili y, quali y and sa e y, as well as sus ainabili y and adap a ion o p o ide he o e all ood
secu i y s a us (The Economis , 2022a).
The e a e ou s a is ical me hods employed in his pape : (1) bi a ia e linea eg ession, (2) bi a ia e
polynomial eg ession, (3) one-way ANOVA, and (4) pai ed T- es . All a e conduc ed in R so wa e. Each
me hod has i s own pu pose. Bi a ia e linea eg ession is used o es he linea co ela ion be ween wo a i-
ables. Polynomial eg ession is used o es he co ela ion be ween wo a iables when he co ela ion is non-
linea . In his con ex , he non-linea i y es ed is loga i hmic. One-way ANOVA is used o compa e whe he
he e is a signi ican di e ence be ween he esul s o linea eg ession and polynomial eg ession. Finally,
pai ed T- es is used o de e mine whe he he e is a signi ican di e ence be ween wo da ase s o he same
sample.
The esea ch s eps begin by es ing bi a ia e linea eg ession o co ela ions be ween income and
ood secu i y, as well as be ween happiness and ood secu i y. This is conduc ed o all coun ies wi hin he
scope o he s udy o each yea . Then, bi a ia e polynomial eg ession o he same co ela ions and scopes is
pe o med. A e wa ds, each o he co esponding linea eg ession model and polynomial eg ession model
a e compa ed agains each o he using one-way ANOVA.
These s eps a e all aken o de e mine whe he he hypo heses a e ue: income and ood secu i y co -
ela ion is polynomial while happiness and ood secu i y co ela ion is linea . A e he one-way ANOVA es -
ing, i he income and ood secu i y co ela ion’s polynomial model shows signi ican di e ence wi h i s linea
model whe e he polynomial model i s be e , i means he hypo hesis ega ding income and ood secu i y
co ela ion is co ec . In con as , i he happiness and ood secu i y co ela ion’s polynomial and linea mod-
els do no show signi ican di e ence when compa ed agains each o he , i means he hypo hesis ega ding
happiness and ood secu i y is co ec .
Be o e del ing in o he esul s o he analysis, he da a used in his pape is p esen ed.
Figu e 1. Equa ion o Reg ession Models
8
N 1/39/2025 I Nauki P zy odnicze i Medyczne
www.naukowcy.o g.pl
Nauki P zy odnicze i Medyczne
Table 1. Desc ip i e s a is ics o a iables used in he s udy
Resul s and discussions
These a e he esul s o bo h linea and polynomial co ela ions be ween income and ood secu i y as
well as be ween happiness and ood secu i y:
Table 2. Resul s o Linea and Polynomial Reg ession o Income-Food Secu i y and Happiness-
Food Secu i y Co ela ions
Jou nal o Li e and Medical Sciences
N 1/39/2025 I Nauki P zy odnicze i Medyczne
9
www.naukowcy.o g.pl
Below is he isualiza ion in he sca e ed plo o he ela ionship be ween income and ood secu i y:
Figu e 2. Visualiza ion o compa ison be ween linea ( ed) and polynomial (blue) eg ession mod-
els o income- ood secu i y co ela ion
10
N 1/39/2025 I Nauki P zy odnicze i Medyczne
www.naukowcy.o g.pl
Nauki P zy odnicze i Medyczne
Figu e 3. Visualiza ion o compa ison be ween linea ( ed) and polynomial (blue) eg ession mod-
els o happiness- ood secu i y co ela ion
Simila ly, below is he isualiza ion in he sca e ed plo o he ela ionship be ween happiness and
ood secu i y:
Jou nal o Li e and Medical Sciences
N 1/39/2025 I Nauki P zy odnicze i Medyczne
11
www.naukowcy.o g.pl
The polynomial and linea eg ession models o bo h income- ood secu i y co ela ion and happiness-
ood secu i y co ela ion a e also compa ed using one-way ANOVA es s. Below a e he esul s:
Table 3. P- alue esul s o one-way ANOVA es s be ween polynomial and linea eg ession mod-
els
The esul s in Table 2 show ha , ac oss 10 yea s, all o he models in bo h co ela ions ha e P- alue
less han 0.05, which means ha he co ela ions a e s a is ically signi ican . Howe e , when he R2- alues
a e obse ed, wi hin he income- ood secu i y co ela ion, he polynomial eg ession model always has highe
R-squa ed alues han he linea eg ession model in all yea s. This means ha he co ela ion consis en ly i s
he polynomial model be e han he linea eg ession model. This is s eng hened by he one-way ANOVA
es esul s in Table 3 showing ha he income and ood secu i y co ela ion compa ison shows P- alues less
han 0.05, which means ha he di e ence in a iance is s a is ically signi ican .
While polynomial eg ession is a be e model o he ela ionship be ween income and ood secu i y
han linea eg ession, he co ela ion be ween happiness and ood secu i y ells a di e en s o y. Acco ding o
Table 2, he di e ence be ween R2- alues o polynomial eg ession model and linea eg ession model only
shows negligibly small di e ences. This is s eng hened by Table 3’s one-way ANOVA esul s o ha co ela-
ion, which shows P- alues g ea e han 0.05, meaning no s a is ical signi icance in he a iance be ween he
wo models. Figu e 2 o e s a isual ep esen a ion o suppo hese esul s. The blue and ed lines a e simila
ac oss all yea s. This is di e en om Figu e 2 whe e he blue and ed lines a e signi ican ly di e en , wi h
he blue line i ing be e o how he da a poin s a e sp ead ac oss he sca e ed g aph in all yea s.
Since polynomial eg ession o e s lexibili y in p edic ing ela ionships wi h cu ed lines, while lin-
ea eg ession uses a s aigh line ha limi s p edic ion o only linea co ela ions, he signi ican di e ence in
a iance be ween polynomial and linea models in income- ood secu i y co ela ion means ha he co ela ion
is be e sui ed o a polynomial model. Con e sely, he insigni ican di e ence in a iance be ween he models
in happiness- ood secu i y co ela ion means ha a linea model is be e sui ed o p edic ing he co ela ion
because in oducing lexibili y in o he model does no imp o e i s p edic ion powe .
O e all, hese esul s demons a e ha he co ela ion be ween income and ood secu i y has a loga-
i hmic na u e, while he ela ionship be ween happiness and ood secu i y has a linea na u e. Fu he mo e,
he igu es show ha , he di ec ion o he co ela ions is posi i e: an inc ease in one a iable co esponds o
an inc ease in he o he . The only di e ence is he inc ease a e: whe eas o income- ood secu i y co ela ion,
he inc ease in ood secu i y diminishes e e y ime he e is a ma ginal inc ease in income; meanwhile, o he
happiness- ood secu i y co ela ion, he inc ease is always consis en ac oss all a iables.
