PSY 2311st Edition Lecture 7 Outline of Last Lecture I. ErrorsII. ValidityIII. MeasurementOutline of Current Lecture II. Test InformationIII. ManipulationIV. Decisions About the Manipulationa. Who is Involved in the Comparisonb. What IV Levels will be Comparedc. What Actions Needed to Vary Levels of the IVd. Verifying the IV With a Manipulation CheckCurrent LectureTest Information● Test is a week from today● Available 12:00 - 12:48● About 60% basic information, 40% practice with conceptsManipulation● Using participants who start the study basically the same● Participants are treated identically ( except for the IV)● You decide who experiences what level of the IV● You standardize the characteristics of the IVDecisions About the ManipulationWho is Involved in the Comparison●Design Definition ExampleBetween Groups Design Different people get different levels of the IVGroup 1- Dove ChocolateGroup 2- Hersheys KissWith -in Subject Design All people get all levels of IVTest 1- Dove ChocolateTest 2- Hersheys KissWhat IV Levels Will be Compared● Presence vs. absence of IV○ presence = experimental group○ absence= control group● Tells us does the IV have an effect compared to doing nothing● Amount of the IV○ Does the amount of change in the DV depend on the amount of the IV?● Dose Response Function -- whatever happens to the DV depends upon the amount of IV● Type of IV○ do different versions of the IV have different effects on the DV?○ Both groups get the IV, just get slightly different versions of it■ Ex: IV= business dress-- dress suit vs. dress skirtWhat Actions Need to Vary the Levels of the IV● Real (event) Manipulation -- actually create different levels of the IV○ always prefered but not always:■ Possible (Gender)■ Practical (Wealth)■ Ethical (Danger)● Instructional Manipulation -- words create the illusion of the manipulation○ hypothetical scenario-- “what if”(participant knows it is not real)● Deception -- lie to give the impression that the IV operates○ Ex: Milgram experiment● Individual Differences -- compare people who already differ in some way○ Ex: Male and female● People who differ in one way usually differ in multiple ways● Not actually an experiment (correlation)● You do not decide who gets what level of the IVVerifying the IV With a Manipulation Check● Measurement of the IV● Shows that -- it occurred as planned or participants experienced it as planned● Makes sure IV really is what its supposed to be● Did you deliver the IV as planned?● Did participants receive the IV as planned?● Was the IV experienced by subjects as
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