Quantitative Methods forResearchers
Paul [email protected]
Your objectives
Pretty general!Landscape/area of experiments
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My objectives
Importance of experimental methodExperiments as evidenceValidityScrutabilityStatistics as model comparison
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Preliminary question?
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Experiments as evidence
Randomness removes certaintyExperiments frame dataWithout frame, no point
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Experimental argument
Theory: X causes YTest: change X and measure YBut:variation (people, stochastic)other things affect Yhard to measure YStatistics pierce through the murk!
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Theories in computing
Thin on the groundName one?Low relevance to applicationsSo experiments are pointless?
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Experimental Computing
Experiments have own valueExperiments inform theoryNarrative contextWe create the objects of study
QUAN, Paul Cairns
Experimental argument
Belief: X causes YA reason for lookingTry: change X and measure YAnalyse carefullyProduce evidence
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Variables
Independent variable (IV, X)Dependent variable (DV, Y)quantitativeConfounding variables
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Devising an experiment
Research question (disposable)One sentenceMay use jargonAnswer is “yes/no” but probably “maybe”Question suggests how to answer it
QUAN, Paul Cairns
Revise your researchquestion
In groups of three or four,eachhave a go at a research question. Take turns to explain and be criticised.Be happy to be wrong/stupid. RQs are disposable.
QUAN, Paul Cairns
Evidence
IfX has really changedY has been properly measuredNothing else has changedThe result was significantThenEvidence that X causes Y
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Value?
Modest but cumulativeOpportunity for falsificationEvidenceIsolation of phenomena
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Not black and white
Experiments are not proofValidityAssumptionsExperiments have a frameEgspeed of gravity
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Write up
Title and abstractAims = lit reviewMethodResultsDiscussion
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Why do we do a literature review?
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Literature
Previous researchDefines the communityWhat and whoImplicit standardImplicit style
QUAN, Paul Cairns
Using literature
ImportanceInterestOriginalityInsight
What’s the purpose of a write up?
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Method section
Aim and hypothesisParticipantsVariablesDesignMaterialsProcedure
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Writing as a tool
Necessaryheadings:writethem!Before you do theexptWhat will sig show?Is it valid?Forcesa dialogueWith self or supervisor
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Fantasy abstract
Write an abstract for your experiment (150-250 words) specifying:What the question isWhy it is interesting/importantWhat was done in the experimentWhat IV and DV areWhat significant results (would) showWhat this means
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Swap abstracts – “homework”
Do you know what the question is?Why is it interesting/important?What is the experimental argument?Do you believe it?What would make it better?
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Reading
Abelson,Statistics as Principled ArgumentHacking,Representing and InterveningCairns, Cox,Research Methods for HCI: chaps 1, 6, 10Harris,Designing and reporting experiments in psychology, 3rdedn
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