Chapter 2- How to Do Experiments

8/16/2019 Chapter 2- How to Do Experiments

1/24

HOW TO DO EXPERIMENTS


2/24

Psychology as a Science

Nature Of Scientic Research

• EmpiricalAll scientifc explanations mst !e !ase" onexpe#iments an" o!se#$ation

•

Rigorous%ase" on goo" theo#etical !ase an" son"metho"ology

• Replicable

Same st"y can !e #e&teste" in "i'e#ent con"ition

• Objective

(onclsion "e#i$e" )#om "ata %*T not pe#sonal opinion


3/24

Psychology as a Science

Objective Of Scientic Research

•

DescribeDesc#i!e a sitation o# phenomenon o!+ecti$ely

• Explain

In$estigate sch sitation !ase" on "esc#iption an" p#o$i"eexplanation

• Predict

%ase" on #esea#ch explanation, a!le to p#e"ict a li-ely

otcome

• Control

%eing a!le to cont#ol an" maniplate sitation !ase" onconf#me" p#e"iction


4/24

.a#ia!les

hat is variables!

A $a#ia!le is something that can !echange", sch as a cha#acte#istic o# $ale/

.a#ia!les a#e gene#ally se" in psychologyexpe#iments to "ete#mine i) changes to onething #eslt in changes to anothe#/

X 0


5/24

.a#ia!les

Any cha#acte#istic that can assme mltiple

$ales o# can $a#y in pa#ticipants/

A $a#ia!le is any )acto# that can !econt#olle" o# change" in an expe#iment/

Tempe#at#e

col"

Room

tempe#at#e

hot

Emotions

Sa"

Happy

Ang#y


6/24

.a#ia!les

"o# man$ t$pe ofvariables!

In"epen"ent .a#ia!le 1I.2

Depen"ent .a#ia!le 1D.2

Ext#aneos .a#ia!le

(on)on"ing .a#ia!le


7/24

.a#ia!les

%ndependent &ariable '%&()

Defnition3 a ci#cmstance ha$ing 4 o#mo#e le$els maniplate" !y theexpe#imente# so that e'ects on the

"epen"ent $a#ia!le can !e o!se#$e"/

The c#ite#ia )o# I.3

maniplation o) $a#ia!le

cont#ol $a#ia!les

#an"om $a#ia!les


8/24

In"epen"ent .a#ia!le

I. Tempe#at#e

col"

Roomtempe#at#e

hot

D.Emotions

Ang#y

Positi$e Negati$e

Wo##y

Sa"

Happy

Exciting

(alm

Maniplation o) $a#ia!les


9/24


I. Tempe#at#e

col"

Roomtempe#at#e

hot

(ont#ol $a#ia!les

(ont#ol3Only 5 le$els a#e

!eingmaniplate"/

Hot tempe#at#e154(62/

(on"ition o) thepa#ticipants!e)o#e

pa#ticipating theexpe#iment/

inst#ctionsgi$en/ inst#ment se"/


10/24


I. Tempe#at#e

col"

Roomtempe#at#e

hot

Ran"om $a#ia!les

Ran"om3Not all the

$a#ia!les can !econt#olle" !y theexpe#imente#/

example3&in"i$i"al"i'e#encesamong thepa#ticipants/

Soltion3& sing

#an"omselection7#an"omassignment8he#e

pa#ticipants ha$ee al chances to


11/24

.a#ia!les

Dependent &ariable 'D&()

Defnition3 The !eha$io# the expe#imente#chooses to meas#e: this !eha$io# may"epen"ent pon the le$els o) the I./

Impo#tant concepts o# ;ey8o#"s )o# D.3

O!se#$e"

Meas#e"(onstant

E'ect


12/24

Depen"ent .a#ia!le

I. Tempe#at#e

D.Emotions

Ang#y

Positi$e Negati$e

Wo##y

Sa"

Happy

Exciting

(alm

Expe#imente# can3 O!se#$e the emotions/ Meas#e the emotions/ The emotions sho8n !y the

pa#ticipants a#e constant/ *n"e#stan" the changes o)

emotions is the e'ect o)"i'e#ent tempe#at#es/


13/24

.a#ia!les

Extraneous &ariable)

• Defnition3 Any $a#ia!les othe# than the I. an" D./ .a#ia!les

that the #esea#che#s !elie$es a'ect D./

• T8o types o) ext#aneos $a#ia!les a#e3

• Participant &ariable*Relate" to in"i$i"al cha#acte#istics o) pa#ticipant that mayimpact ho8 they #espon"/ These )acto#s can incl"ecapa!ility, "esi#e, intelligence o# othe# cha#acte#istics thata#e ni9e to each pe#son/

• Situational &ariables*

These ext#aneos $a#ia!les a#e #elate" to things in theen$i#onment that may impact ho8 each pa#ticipant#espon"s, sch as time o) the "ay, con"ition o) la!o#ato#y/


14/24

.a#ia!les

Confounding &ariable)

• Defnition3 An ext#aneos $a#ia!le8hose p#esence a'ects the$a#ia!les !eing st"ie" so thatthe #eslts yo get "o not #e


15/24

(on)on"ing .a#ia!le

I. Tempe#at#e

D.Emotions

Ext#aneos $a#ia!le3Pa#ticipant $a#ia!les

%o"y>stempe#at#e

Pa#ticipant>sexpe#ience

?acility at

the la!

Ext#aneos $a#ia!le3Sitational $a#ia!les


16/24

Th#eats to Inte#nal .ali"ity

The con)on"ing $a#ia!les a#e th#eatening

to the inte#nal $ali"ity o) expe#iments/

Inte#nal $ali"ity means it is ce#tain that it

8as the maniplation o) the I. thatcase" the change in the D./

To a$oi" con)on"ing $a#ia!les in theexpe#iments, 8e nee" to n"e#stan" the$a#ios possi!le th#eats to inte#nal$ali"ity/


17/24


The#e a#e @ th#eats to inte#nal

$ali"ity3/ Histo#y

4/ Mat#ation

5/ Selection

B/ Mo#tality

C/ Testing/ Statistical #eg#ession

@/ Inte#actions 8ith selection


18/24


The#e a#e @ th#eats to inte#nal $ali"ity3

+* "istor$A change in the D. "e to the occ##ence o) ane$ent !et8een the testing o) le$els o) the I./

Example3

To see the e'ecti$eness o) online teaching inimp#o$ing g#a"es 8ithin 4 semeste# t#ials/

Histo#y th#eats3•. st"ents may engage in othe# )o#m o) online

acti$ities othe# than in la!/

•. *ni$e#sity has impose" that online lea#ning is

complso#y to !e ta-en/

Metho"s o)teaching

St"ents>g#a"es


19/24


,* -aturation

A change in the D. "e to pa#ticipants> agingo# !ecoming mo#e expe#ience" !et8een thea"minist#ation o) le$els o) the I./

Mat#ation can !e a p#o!lem in long&te#mexpe#iments o# 8hen pa#ticipants a#en"e#going #api" change/

Example3 Expe#iment sing chil"#en aspa#ticipants/ The#e is a hge gap inpsychomoto# a!ilities !et8een to""le#s age"4 an" 5 yea#s ol" 1 yea#2


20/24


.* Selection

A change in the D. "e to expe#imente#scannot assign pa#ticipants #an"omlyexpose" to "i'e#ent le$els o) the I./

Example3

Metho"s o)teaching

St"ents>g#a"es

Onlineteaching

(lass&!ase"teaching

Ma-ing s#e that pa#ticipantsa#e #an"omly "ist#i!te"!et8een 4 le$els in te#ms o)3Intelligence le$elsS-ills le$els

Demog#aphical $a#ia!les


21/24


/* Statistical regression

This te#m #e)e#s to the )act that 8henexpe#imente#s choose pa#ticipants on the!asis o) thei# ha$ing sco#e" $e#y high o# $e#ylo8 on a pa#ticla# test, thei# sco#es ten" to

mo$e to8a#" the mean on a secon" test/

Example3 In o#"e# to examine thee'ecti$eness o) ce#tain e"cational

p#og#am, the expe#imente# ten" to chooseonly st"ents 8ho ha$e lo8e# o) I sco#e to!e the pa#ticipants/


22/24


0* 1esting

A change in the D. "e to pa#ticipants> p#io#expos#e to the testing inst#ment o#sitation/

Testing can !e a th#eat to inte#nal $ali"ity

8hen the expe#imente# sensitiFing thesitation in the p#etest/

Example3 In examine the e'ecti$eness o)GTa- Na- a"$e#tising campaign on the

a8a#eness o) the p!lic, the expe#imente#"esign the p#etest an" postest expe#iment/

P#etest PosttestSho8ing GTa-Na-a"$e#tisement

As-ing 9estionsa!ot $a#iossmo-ing campaign

Testing th#eat A p#etest can also p#o$i"ein)o#mation ths inc#easingthe pa#ticipant>s -no8le"geo) a topic so that sco#es onthe posttest 8ill !e highe#/


23/24


2* -ortalit$

Pa#ticipants "#opping ot o) an expe#iment/Di'e#ential mo#tality is a th#eat to inte#nal$ali"ity 8hen mo#e o# "i'e#ent -in"s o)pa#ticipants "#op ot o) the g#ops assigne"

to $a#ios le$els o) the I./Example3 to test the e'ecti$eness o) st#ess&inoclate p#og#am on nm!e# o) complaintsamong manage#s/

#op 3manage#sexpose tost#ess&inoclatep#og#am

#op 43manage#s8ithot thep#og#am


24/24


3* %nteractions #ith selection

A th#eat to inte#nal $ali"ity case" !y$ali"ity th#eat sch as mat#ation an"histo#y inte#acting 8ith the th#eat o)selection/

In othe# 8o#"s, inte#actions 8ith selection isa com!ination o) inte#action o) 5 -in"s o)th#eats: mat#ation, histo#y an" selection/

Example o) the case 3 please #e)e# to thepage o) 5@/

Documents

Chapter 2- How to Do Experiments