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Quantitative Methods for Researchers. Paul Cairns paul.cairns@york.ac.uk. Your objectives. Pretty general! Landscape/area of experiments. My objectives. Importance of experimental method Experiments as evidence Validity Scrutability Statistics as model comparison. Preliminary question?.
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Quantitative Methods forResearchers Paul Cairns paul.cairns@york.ac.uk
Your objectives • Pretty general! • Landscape/area of experiments
My objectives • Importance of experimental method • Experiments as evidence • Validity • Scrutability • Statistics as model comparison
Experiments as evidence • Randomness removes certainty • Experiments frame data • Without frame, no point
Experimental argument • Theory: X causes Y • Test: change X and measure Y • But: • variation (people, stochastic) • other things affect Y • hard to measure Y • Statistics pierce through the murk!
Theories in computing • Thin on the ground • Name one? • Low relevance to applications • So experiments are pointless?
Experimental Computing • Experiments have own value • Experiments inform theory • Narrative context • We create the objects of study QUAN, Paul Cairns
Experimental argument • Belief: X causes Y • A reason for looking • Try: change X and measure Y • Analyse carefully • Produce evidence
Variables • Independent variable (IV, X) • Dependent variable (DV, Y) • quantitative • Confounding variables
Devising an experiment • Research question (disposable) • One sentence • May use jargon • Answer is “yes/no” but probably “maybe” • Question suggests how to answer it QUAN, Paul Cairns
Revise your research question In groups of three or four, each have 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 • If • X has really changed • Y has been properly measured • Nothing else has changed • The result was significant • Then • Evidence that X causes Y
Value? • Modest but cumulative • Opportunity for falsification • Evidence • Isolation of phenomena
Not black and white • Experiments are not proof • Validity • Assumptions • Experiments have a frame • Eg speed of gravity
Write up • Title and abstract • Aims = lit review • Method • Results • Discussion
Literature • Previous research • Defines the community • What and who • Implicit standard • Implicit style QUAN, Paul Cairns
Using literature • Importance • Interest • Originality • Insight
Method section • Aim and hypothesis • Participants • Variables • Design • Materials • Procedure
Writing as a tool • Necessary headings: • write them! • Before you do the expt • What will sig show? • Is it valid? • Forces a dialogue • With self or supervisor
Fantasy abstract • Write an abstract for your experiment (150-250 words) specifying: • What the question is • Why it is interesting/important • What was done in the experiment • What IV and DV are • What significant results (would) show • What this means
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?
Reading • Abelson, Statistics as Principled Argument • Hacking, Representing and Intervening • Cairns, Cox, Research Methods for HCI: chaps 1, 6, 10 • Harris, Designing and reporting experiments in psychology, 3rd edn