Kuliah 9 -Kesahan Dan Kebolehpercayaan Instrumen

8/16/2019 Kuliah 9 -Kesahan Dan Kebolehpercayaan Instrumen

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OBJEKTIF

1.Dapat menjelaskan maksud kesahan dankeboleh percayaan sesuatu alatpengukuran penyel d kan

!.Dapat menghura kan jen s"jen s kesahandan keboleh percayaan alat pengukuran

yang d gunakan dalam penyel d kan


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KE#$%$&

'($)IDIT*+

KEBO)E%,E- $*$$&'-E)I$BI)IT*+


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(al d ty re/ers to the degree n0h ch our test or other measur ng

de ce s truly measur ng 0hat0e ntended t to measure.

#ejauh mana alatmengukur apa yang a

sepatutnya ukur


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Kesahan sesuatu alat pengukuran merujuk kepadasejauh manakah alat yang digunakan mengukur datayang dikehendaki untuk mencapai objektif kajian(Mohd Majid Konting, 1990)

Kesahan bermaksud kebolehan ujian mengukur apayang sepatutnya diukur, Youngman !ggleston, 19"#$%a& 'e ton, 199 )


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Kesahan 2agasan

Kesahan KandunganKesahan Kr ter a

ontent 'representat e o/all poss ble 3uest ons thatcould be asked+

r ter on"re/erenced 'scores are apred ctor o/ an outcome or cr ter on

they are e4pected to pred ct+

onstruct'determ nat on o/ the

s gn / cance5 mean ng5

purpose5 and use o/ thescores )

Content validation is usually carriedout by experts

Based on content

Based on -elat onsto Other (ar ables

oncurrentE dence

,red ct eE dence

Based on Internal #tructure


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%ejauh mana alat merangkumi kandungan sesuatubidang*

Matlamat utama ialah untuk memastikan semua isidan kandungan bidang yang diukur menggambarkanbidang tersebut*

+erdasarkan kepada skop dan objektif dan

kandungan sesuatu bidang yang dikaji* endapat pakar atau penilai luar diperlukan bagimenilai kesesuaian butiran bagi domain yang dipilih*

Kesahan Kandungan(Content Validity )


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-is concerned ith a test.s ability to include or representall of the content of a particular construct* /he

uestion 1 2 1 3 4445 may be a 6alid basic additionuestion* 7ould it represent all of the content that

makes up the study of mathematics8 t may beincluded on a scale of intelligence, but does itrepresent all of intelligence8 /he ans er to these

uestions is ob6iously no* /o de6elop a 6alid test ofintelligence, not only must there be uestions on math,

but also uestions on 6erbal reasoning, analyticalability, and e6ery other aspect of the construct e callintelligence* /here is no easy ay to determinecontent 6alidity aside from e&pert opinion*


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1* :o the items appear to represent the thingyou are trying to measure8

#* :oes the set of items underrepresented

the construct.s content (i*e*, ha6e youe&cluded any important content areas ortopics8)

;* :o any of the items represent somethingother than hat you are trying to measure(i*e*, ha6e you included any irrele6antitems8)


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Sebelum sesuatu instrumen itu dikatakanmempunyai kesahan kandungan, lima syarat ini

perlu dipenuhi:

1*+idang kandungan mestilah dinyatakan dalam bentuktingkah laku yang secara umum diterima maknanya*#*+idang mestilah dihuraikan dengan jelas*;* +idang mestilah rele6an dengan tujuan penggunaanujian*

hakim yang berkelayakan mestilah bersetujubaha a bidang telah disampel secara mencukupi*


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/o measure se6eral components or dimensions of aconstruct*

?se @actor Analysis to analyBes correlations amongtest items and tells you the number of factorspresent* ts tell you hether the test isunidimensional or multidimensional*

?nidimensional C all the item measure are singleconstruct*

Multidimensional C different set of item tapdifferent construct or different component of abroader construct*

E dence Based on Internal#tructure


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@actor analysis tell you ho many dimensions orfactors your test items represent*

Also can obtain a measure of test homogeneity(i*e*, the degree to hich the different items

measure the same construct or trait) ?se coefficient alpha (Alpha Dronbach) for the testof homogeneity*

f the alpha is lo (e*g*, E* 0) for the test, thensome items might be measuring different

constructs or some items might be bad* !&amine the items that are contributing to yourlo coefficient alpha and consider eliminating orre6ising them*

66 Internal #tructure


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Fbtained by relating your test scores to a rele6ant criterion* A criterion is the standard or benchmark that you ant to

predict accurately on the basis of scores from your test* %ejauh mana kaitan antara alat dengan kriteria luaran yang

berkecuali (sama ada item mengukur kriteria yang hendakdiukur)*

:itentukan dengan analisis korelasi antara dua set markah* Dalculate correlation coefficients for the study of 6alidity C

validity coefficients *

Kesahan Kriteria(Criterion Validity)


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Doncurrent Galidity refers to a measurement device’s ability to varydirectly with a measure of the same construct or indirectly with ameasure of an opposite construct * t allo s you to sho that your

test is 6alid by comparing it with an already valid test *Administering the focal test and criterion test at appro&imately thesame point in time (i*e*, concurrently) and then correlating the t oset of scores* f the t o sets of scores highly correlated, you ha6e

concurrent e6idence*

$ ne0 test o/ adult ntell gence5 /or e4ample5 0ould ha econcurrent al d ty / t had a h gh pos t e correlat on 0 th the

7echsler $dult Intell gence #cale s nce the 7echsler s anaccepted measure o/ the construct 0e call ntell gence. $n

ob ous concern relates to the al d ty o/ the test aga nst0h ch you are compar ng your test. #ome assumpt ons must

be made because there are many 0ho argue the 7echslerscales5 /or e4ample5 are not good measures o/ ntell gence.

e.g.


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n order for a test to be a 6alid screening de6ice for somefuture beha6ior, it must ha6e predicti6e 6alidity* /he %A/ is

used by college screening committees as one ay to

predict college grades * /he HMA/ is used to predictsuccess in business school * And the I%A/ is used as a meansto predict la school performance * /he main concern ith

these, and many other predicti6e measures is predicti6e6alidity because ithout it, they ould be orthless

8 Obta n pred ct e e dence o/ al d ty by measur ng yourpart c pants at one po nt n t me on your test and then5 at a/uture t me5 measur ng them on the criterion measure.

8 Take more t me and e//ort than concurrent e dence5 but tcan pro de super or e dence that your test does 0hat

you 0ant t to do.


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-el ab l ty s synonymous 0 th the cons stency o/ a test5 sur ey5obser at on5 or other measur ng de ce. Imag ne stepp ng on your

bathroom scale and 0e gh ng 19: pounds only to / nd that your 0e ght on

the same scale changes to 1;: pounds an hour later and 1:: pounds anhour a/ter that. Base on the ncons stency o/ th s scale5 any researchrely ng on t 0ould certa nly be unrel able. ons der an mportant study ona ne0 d et program that rel es on your ncons stent or unrel able bathroom

scale as the ma n 0ay to collect n/ormat on regard ng 0e ght change.7ould you cons der the r results accurate<


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%ejauh mana instrumen mengukur dengan tekal apayang hendak diukur*

%cores from measuring 6ariables that are stable andconsistent


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Test"retest-el ab l ty

E3u alent

Forms-el ab l ty

Internalons stency-el ab l ty


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=erujuk kepada ketekalan atau stab l t markahuj an j ka d lakukan pada masa yang berbe>a.

ontoh?@j an d ber kan kepada 1:: nd du untuk satu masa dan d ulangpada masa berla nan. Dua set markah n d korelas kan. #ek ranya

nd du memperoleh markah tert ngg dalam uj an 1 jugamemperoleh markah tert ngg dalam uj an !5 beg tu juga nd duyang mendapat markah terendah dalam uj an 1 juga mendapat

markah terendah dalam uj an5 maka d katakan mempunya korelasyang t ngg . Oleh tu soalan uj an tersebut mempunya

kebolehpercayaan yang t ngg .


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Jefers to the consistency of a group of indi6idual.s scores on t oe ui6alent forms of a test designed to measure the samecharacteristic*

Menggunakan satu alat yang dibina dan satu lagi yang pia ai* :itadbir ke atas subjek yang sama dan pada masa yang sama

atau masa yang lain* ! ui6alent form means that t o tests are constructed so that

they are identical in e6ery ay e&cept for the specific itemsasked on the test*

/his means that they ha6e the same number of items, the itemsare the same difficulty le6el, the item measure the sameconstruct, and the test is administered, scored, and interpretedin the same ay*

/he t o set of scores are than correlated* f this reliabilitycoefficient to be 6ery high and positi6e, that is the indi6iduals

ho do ell on the first form of the test should also do ell onthe second form, and indi6iduals ho performed poorly on thefirst form of the test should perform poorly on the second test*


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nternal consistency refers to ho consistently the items on atest measure a single construct or concept*

/he test>retest methods of assessing reliability are generalmethods that can be used ith just about any test*

nternal consistency measures are con6enient and are 6erypopular ith researchers because they re uire one group ofindi6iduals to take the test one time*

/ o inde&es of internal consistencyo %plit half reliabilityo Doefficient alpha


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8 #pl tt ng a test nto t0o e3u alent hal es and thenassess ng the cons stency o/ the scores across the t0ohal es o/ the test.

8 D de the test nto hal es and correlate the scores/rom the t0o hal es.

8 ompute the correlat on bet0een scores on the t0o

hal es o/ the test us ng #pearman"Bro0n /ormula.8 The lo0 correlat on nd cates that the test 0as

unrel able5 a h gh correlat on nd cates that the test 0asrel able.

#pl t"hal/ rel ab l ty


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8 )ee ronbach 1A 1+ de eloped coe// c ent alpha.. AlphaCronbach

8 oe// c ent alpha tells you the degree to 0h ch the temsare nterrelated.

-ule o/ thumb?

8 $t a m n mum5 greater than or e3ual to .:C /or research

purposes and some0hat greater than that alue 'e.g. .:A+ /or cl n cal test ng purposes.

oe// c ent alpha


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ernyataan item mestilah jelas dan tepat* Arahan mestilah jelas dan ringkas* tem hendaklah bentuk sejenis* %ituasi dan masa pengukuran hendaklah pia ai,

serupa dan terka al* !lakkan gangguan ke atas subjek*

!lakkan kebimbangan subjek dengan memberijaminan keselamatan dan kerahsiaan ke atasmaklumat yang diberi*


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Fasa terakh r t njauansebelum pengumpulan

data bermula.

=atlamatnya adalah untuk

mencar masalah dalam soalsel d k5 termasuk soalan yang

lemah5 arahan yang t dak lengkapdan tem yang sukar d ja0ab.


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Jumlah responden t dakd tentukan dengan tepat5d cadangkan sekurang"

kurangnya ! orang5 leb h ba kantara : C orang.

@ntuk kaj anbaharu5lakukan dua

kal uj an r nt s.

T dak boleh gunakankumpulan /okus

sebenar.


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Trainresearchers to

collectobservational

data

Respect individuals and sitesduring data gathering (ethics)

Developstandard written

procedures foradministering aninstrument

btainpermission to

collect anduse public

documents


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Documents

Kuliah 9 -Kesahan Dan Kebolehpercayaan Instrumen