Choosing Statistical Procedures for Research Problems

8/9/2019 Choosing Statistical Procedures for Research Problems

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STATISTICALPROCEDURES FOR

RESEARCH PROBLEMS


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Each statistical procedure has a setassumptions for its appropriate app

In selecting among procedures, anyresearcher must therefore considernumber of factors such as the follow

General and Specic Purpose of Res ype of !uestions"#ypothesis General ype of Statistic


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Research $uestions can be di%ided intobroad types:

&I''ERE()E◦ Is * di+erent from -

◦ Is there a di+erence between * and -

◦ *re there di+erences among *, and )-

*SS)I*I(*/◦ Is * associated or related with -

◦ Is there a correlation between * ad -

◦ 0hat is the relationship between * and -


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&ES)RIPI1E◦ 0hat is the mean %alue of *-

◦

0hat are the usual %alues in *-


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GE(ER*/

P2RPSE

E4P/RE RE/*I(S#IP E0EE(

1*RI*/ES

&

SPE)I'I)

P2RPSE

)8P*RE

GR2PS

'I(& SRE(G#

'

*SS)I*I(S,

RE/*E 1*RI*/E

S28

6PE '!2ESI("

#6P#ESIS

&I''ERE()E *SS)I*I(*/ &

GE(ER*/ 6PE '

S*ISI)

&I''ERE()E

I('ERE(I*/

S*ISI)S

*SS)I*I(*/

I('ERE(I*/

S*ISI)S

&

S

LEVEL OF DIFFERENCE ASSOCIATIONAL D


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LEVEL OF

MEASUREMEN

T

DIFFERENCE

INFERENTIAL

STATISTICS

ASSOCIATIONAL

INFERENTIAL

STATISTICS

D

S

Nominal

• Chi-Squar

;test for

proportion

Phi )oe


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Di.rn! r$ar!h qu$#ion$/these $uestions, we compare score

the dependent %ariable7 of two or mdi+erent groups, each of which iscomposed of indi%iduals with one of%alues or le%els on the independent

%ariable. his type of $uestion attemto demonstrate that groups are notsame on the dependent %ariable.


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A$$o!ia#ional r$ar!h qu$#ion$/these $uestions, we associate or relate

or more %ariables. his approach usuain%ol%es an attempt to see how two ormore %ariables co;%ary 5e.g., higher %aon one %ariable correspond to higher o

lower %alues on another %ariable for thsame persons7 or how one or more%ariables enables one to predict anoth%ariable


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D$!ri0#i) r$ar!h qu$#ion$/ hese are not answered with infere

statistics. hey merely describe orsummarie data, without trying togeneralie to a larger population ofindi%iduals


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* )aria1l is dened as a characteristic of the partisituation for a gi%en study that has di+erent %alues study and must be able to %ary or ha%e di+erent %al

Gender: 8ale or 'emale *ge: has a large number of %alues ype of reatment"Inter%ention

In $uantitati%e research, %ariables are dened opera

and are commonly di%ided into in'0n'n# )aria5acti%e or attribute7, '0n'n# )aria1l$, and 2)aria1l$.


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two types of independent%ariables

*)I1E *RI2E


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*lso >nown as manipulated indepen%ariable.

*n acti%e independent %ariable is a%ariable such as wor>shop, newcurriculum, or other inter%ention, atleast one le%el of which is gi%en to a

group of participants, within in aspecied period of time during the s

A!#i) in'0n'n# )aria1l$


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*lso >nown as measure independent %a%ariable that cannot be manipulated, ye

ma?or focus of the study. he %alues of the attribute independent

are pre;e@isting attribute of the personsongoing en%ironment that are not syste

changed during the study. E@amples are education, gender, age, e

group, I! and self;esteem. Studies with attribute independent %ariables are calle

20rimn#al studies.

A##ri1u# in'0n'n# )aria1l$


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he dependent %ariable is assumed to measureassess the e+ect of the independent %ariable.

It is thought of as the presumed outcome or cr &ependent %ariables are often test scores, ratin

$uestionnaires, readings from instruments or mof physical performance.

/i>e independent %ariables, dependent %ariable

ha%e at least two %aluesA most dependent %ariamany %alues, %arying from low to high so they easy to diagram as the independent %ariable.

D0n'n# Varia1l


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E@traneous %ariables 5also >nown as nuisancco%ariates in some designs7 that are not of i

a particular study but could inBuence the de%ariable. En%ironmental factors 5e.g. temperature or

distractions7, time of day and characteristicse@perimenter, teacher or therapist are some

e@traneous %ariables that need to be contro

E2#ranou$ Varia1l


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P*R*8ERI) ES

Independent 1ariableis between;sub?ects

Independent 1ariablehas C categories

Independent groups t-test

Independent 1ariable

has D or morecategories

ne;way between;sub?ects analysis of

%ariance 5';test7

Independent 1ariableis within;sub?ects

Independent 1ariablehas C categories

)orrelated groups

t-test

Independe

has D ocateg

ne;way measures

%aria

5';t


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((P*R*8ERI) ES

Independent1ariable is between;

sub?ects

Independent1ariable has C

categories

0ilco@on ran> sumtest " 8ann;0hitney

2 test

or )hi;S$uare test

Independent1ariable has D ormore categories

rus>al;0allis

#;test or

)hi;s$uare test

Independent1ariable is within;

sub?ects

Independent1ariable has C

categories

0ilco@on

signed;ran> test

Indepen1ariable hmore cate

'riedman a%ariance b

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Choosing Statistical Procedures for Research Problems