sampling process and measurement scale

7/24/2019 Sampling process and measurement scale

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The DataCollection Process:

ResearchBy: Bryan Mae Degorio


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Objectives:

Defne population and population sample.Discuss probability and nonprobability

methods o sampling.

Discuss the dierent procedures used ineach sampling method including theiradvantages and disadvantages.

Criticize the sampling procedures used in

dierent articles or research report.

11/23/1 !pollo "ram#ell $ursing %chool 2


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Content:

&opulation sampling

'ypes o sampling

%ampling procedures(ethods o data

collections)

* intervie#+

,uestionnaire+ observationalprocedure+ li-ert scale+mechanical instrument andpsychological or sociologicalinstrument

(easurement o

variables in researchData processing

Data analysis andinterpretation.



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Population and Sampling Process

Population reers to the complete

set o persons or

objects that possessthe same character ointerest to theresearcher.

! "roup o Population

a. 'arget population

b. %tudy population

Samples ! subseto population

selected to represent thepopulation

Sample rame# a list o #hich thesampling unit #ithin apopulation are individuallynamed or numbered

$lement

* reers to the singlemember o a population

11/23/1 !pollo "ram#ell $ursing %chool


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Men bet%een !!' in Canada

Men bet%een !!' in Ontario

(ou prepare asample rame orthose men inOntario# name or

numberThe ) o sampleyou %ill ta*eamong those menin Ontario


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Sampling is the method o selecting sample rom the population

'ypes o sampling

a. &robability sampling

b. $on* probability sampling



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Probabilitysampling+

!-a) Randomsampling

t involves the use o

random samplingselection process toobtain sample or anelement o a

populationts main goal is to

obtainrepresentative

elements o theo ulation.

Types o ProbabilitySampling:

1. %imple randomsampling

2. %tratifed randomsampling

3. Cluster randomsampling

. %ystematic randomsampling


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rator.asp
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,on#Probability Sampling4'he sample element

are chosen rom thepopulation be anonrandommethod

'here is no %ay thatthe probability obeing included in theparticular samplecan bedetermined-

Types o non#probability sampling:

1. Conveniencesampling

2. 5uota sampling

3. &urposive sampling11/23/1 !pollo "ram#ell $ursing %chool 6


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Deciding the S.MP/$ S01$+

$ote) there is ,O$2.CT value

%uggestions)a. 7btain as manysub8ects as possible

b. 'hings to consider)

data collection techni,ue &rocedure or recruitment

'he cost

9ternal validity

:hen to ta-e largesamples)

1. (any uncontrolled variablesare present

2. %mall dierences are epectedin members o population

3. &opulation must be divided into

subgroups. Drop*out rate is epected to be

high

. %tatistical test are used thatre,uires minimum sample size

11/23/1 !pollo "ram#ell $ursing %chool 1;


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a- Po%er analysis# isa procedure use to

determine thesample size

b- Sampling error#the dierencebet#een the data

obtained rom therandom sample andthe data that #ouldbeen obtained i anentire population#ere measured

c- Sampling bias#occurs #hen thesamples are notcorrectly selected.



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Sample Si3e

4,5

Margin o $rror

4raction5

Margin o $rror

4percentage5

6& ;.31 31.

!& ;.22 22.

7& ;.11 1.16&& ;.1;; 1;.;

!&& ;.;01 0.1

7&& ;.; .

6&&& ;.;32 3.2

!&&& ;.;22 2.2

7&&& ;.;1 1.

6&&&& ;.;1; 1.;


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Measurements+-

s the processassigning numbersto variables.

t implies8uanti9cation ovariables orinormationby

assigning number toa data.

/evels oMeasurements:

1. $ominal scale

2. 7rdinal scale3. nterval scale

. nternal scale



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,ominal Scale $umbers are assigned to

variables that are mutuallyeclusive and dierent romone another.

$: 6; male and !;emale

0nterval Scale

'here is an actual e,ual intervalsize bet#een measurements

!bsence o zeros points

9: Temperature< /i*ert scale

Ordinal Scale !n order/ran-ing is imposed on

categories and the number mustpreserve orders.

'he distance bet#een ran-s are

not e,ual or sometimes notmeasured.

$: 6; tallest< !; nettallest< =rdthird tallest

Ratio Scale

'he highest orm o measurement. 'here is continuum o values #ith

an absolute zero points

9) age< gender< test scores



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$rrors in Measurement+


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Reliability# Reers to the consistency

%ith %hich the instrumentor test measures %hateverit is suppose to measure

(easures o reliability)

a. 'est*retest reliability

b. nternal consistencyvalidity



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Data Collection Methods+

Things to consider in data collection:

a. :ho #ill collect the data

b. :hen the data #ill be collected=

c. :here the data #ill be collected=

d. :hat data #ill be collected=e. >o# the date #ill be collected=

(ethods4.

1. 7bservational methods2. ntervie#s

3. 5uestionnaire


sampling process and measurement scale

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