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'n Illustrasie van hoe 'n steekproef uit die bevolking gekies word

Om resultate te verkry wat verteenwoordigend is, is die van kritieke belang om 'n verteenwoordigende steekproef te kry. Byvoorbeeld, as ons wou bepaal hoe groepsdruk die besluit om te begin rook, beïnvloed - dan sou die resultate baie anders gewees het as slegs seuns ondervra is, in vergelyking met 'n studie waar onderhoude met beide seuns en meisies gevoer is.

Daarom moet vrae soos: "Hoeveel onderhoude word benodig?" en "Hoe kies ons kandidate vir onderhoude?" tydens die ontwerpfase van die steekproefproses gevra word.

Die mees akkurate resultate word verkry indien die hele bevolking gebruik word as steekproef vir 'n opname, maar dit kan baie duur wees en/of baie lank neem. Die tweede beste metode is om 'n steekproef ewekansig te kies. Dit beteken dat elke lid van die bevolking 'n gelyke kans het om geselekteer te word, onafhanklik van hoe die lede gekies word. Daar is verskeie metodes om lede op hierdie manier te kies, byvoorbeeld, name kan uit 'n hoed getrek word. Meeste moderne wetenskaplike sakrekenaars het 'n sleutel wat mens kan druk om ewekansige getalle te genereer wat mens kan gebruik om 'n steekproef te kies. Sigbladpakkette op 'n rekenaar het ook gewoonlik so 'n funksie.

So, as jy byvoorbeeld 'n bevolking van 1 000 leerders in jou skool het, kan jy moontlik 100 leerders ewekansig kies en dit sal dan die steekproef wees wat jy vir die opname gebruik.

Voorbeelde van datastelle

Die res van hierdie hoofstuk handel oor die wiskundige besonderhede wat nodig is om data wat versamel is, te analiseer.

Hier volg nou 'n paar voorbeelde van datastelle wat gebruik kan word om die metodes wat toegepas word, te verduidelik.

Datastel 1: gooi van 'n muntstuk

'n Ewekansige muntstuk is 100 keer gegooi en die kant waarop die muntstuk land, is opgeneem (kop of stert). Die data is opgeneem in "Datastel 1: Gooi van 'n muntstuk" .

Resultate wanneer 'n ewekansige muntstuk 100 keer gegooi word. K beteken dat die muntstuk met sy kop na bo geland het terwyl S beteken dat die muntstuk met sy stert na bo geland het.
K S S K K S K K K K
K K K K S K K S S S
S S K S S K S K S K
K K S S K S S K S S
S K K K S S K S S K
K S S S S K S S K K
S S K S S K S S K S
K S S K S S S S K S
S K S S K K K S K S
S S S K K S S S K S

Datastel 2: gooi van 'n dobbelsteen

'n Ewekansige dobbelsteen is 200 keer gegooi en die waardes waarop die dobbelsteen land, is opgeneem. Die data is opgeneem in "Datastel 2: Gooi van 'n Dobbelsteen" .

Resultate wanneer 'n ewekansige dobbelsteen 200 keer gegooi word
3 5 3 6 2 6 6 5 5 6 6 4 2 1 5 3 2 4 5 4
1 4 3 2 6 6 4 6 2 6 5 1 5 1 2 4 4 2 4 4
4 2 6 4 5 4 3 5 5 4 6 1 1 4 6 6 4 5 3 5
2 6 3 2 4 5 3 2 2 6 3 4 3 2 6 4 5 2 1 5
5 4 1 3 1 3 5 1 3 6 5 3 4 3 4 5 1 2 1 2
1 3 2 3 6 3 1 6 3 6 6 1 4 5 2 2 6 3 5 3
1 1 6 4 5 1 6 5 3 2 6 2 3 2 5 6 3 5 5 6
2 6 6 3 5 4 1 4 5 1 4 1 3 4 3 6 2 4 3 6
6 1 1 2 4 5 2 5 3 4 3 4 5 3 3 3 1 1 4 3
5 2 1 4 2 5 2 2 1 5 4 5 1 5 3 2 2 5 1 1

Datastel 3: massa van 'n brood

In Suid-Afrika is daar regulasies oor die vervaardiging van brood om verbruikers te beskerm. Hier is 'n uittreksel uit 'n verslag oor die wetgewing:

"Wetgewing vereis dat 'n brood 800g moet weeg indien dit nie gemerk is nie, met 'n speling van 5 persent bo en 10 persent onder hierdie massa. Die gemiddelde massa van 10 van hierdie brode moet egter presies die aangeduide massa wees." - Sunday Tribune op 10 Oktober 2004, bladsy 10.

Questions & Answers

what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
How can I make nanorobot?
Lily
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
how can I make nanorobot?
Lily
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Siyavula textbooks: wiskunde (graad 10) [caps]. OpenStax CNX. Aug 04, 2011 Download for free at http://cnx.org/content/col11328/1.4
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