# Math W50: How do they know my opinion? # January, 2000 Monday, January 3 Note: No Class Tuesday, January 4 Note: No Class Wednesday, January 5 Note: No Class Thursday, January 6 Topic: Introduction Topic: 7 Critical Components @ overheads/seven-critical.shtml Topic: Measurement Act: Survey 1 @ data/survey01.txt Act: Survey 2 @ data/survey02.txt Read: Utts 1-3 Vocab: Vocab: statistics, 7 critical components, Vocab: individual (unit), variable, value of variable, Vocab: categorical variable, measurement variable, Vocab: discrete, continuous, validity, reliabilty, bias, variability #Note: Class begins 2pm in NH 295 course intro, student intros, why you are in the course Def of stats get student ideas (on board) more than one use of word statistics descriptive (summary measures) inferential some defs (primarily of inferential statistics) Utts: a collection of procedures and principles for gaining information in order to make decisions when faced with uncertainty Amabile: a way of taming uncertainty, of turning raw data into arguments that can resolve profound questions Moore: the science of gaining information from numerical data Garfunkel: the science of drawing conclusions from data with the aid of the mathematics of probability dictionary: the mathematics of the collection, organization, and interpretation of numerical data, especially the analysis of a population's characteristics by inference from sampling etymology: latin: statisticus - of state affairs political right down to etymology key elements data uncertainty information/decision-making ability science or math? Video - Against All Odds #1: beginning thru about 13:30, 26:00 to end [whole thing if time -- but probably not] Video - FAPP #6 beginning to about 4:00 Three phases of a statistical study (and outline of course) 1) collect data (statistical design) 2) organize data (data analysis) 3) draw conclusions from data (statistical inference) Survey 1: Have students add to existing list collect data from students, have them gather 2 more each Quiz 0: info about students ----------- Break ----------- Fill out survey 1 and survey 2 7 critical components that determine soundness of statistical studies 1) source of funding (why was it done?) 2) researcher contact 3) individuals studied and how selected 4) measurements made (quesitons asked) 5) setting 6) extraneous differences (other explanations for effect) 7) magnitude of claimed effect example: drug to cure excessive barking in dogs (page 22) example: US Voters Focus on Selves, Poll says (from Moore S:C&C) example: most women unhappy in their choice of husbands (page 24) didn't do this one How data are organized: units/individuals/subjects variables values of variables immagine a grid layout Some terminology categorical vs. measurement variables continuous vs. discrete validity (proxies) reliability bias -- systematically off in same direction variability pictures of variability/bias possibilities (target) Apply terminology to Survey 1 Summary -- Measuring is a difficult task example: finding cheapest grocery store Survey 2: Wording issues did questions 1 and 2 in class data: 1) 6-0; 0-6 in expected direction 2) 2-4; 2-4 in expected direction Wording Pitfalls Bias (Intentional or unintentional) Elian Gonzalez Do you agree that he should be returned to his father in Cuba? [with US Immigration and Naturalization Service] Do you agree that he should be allowed to remain with his relatives in Florida? [agree with boy's attorneys] Confidentiality and Anonymity (people may lie) Desire to Please "How much do you smoke?" vs. cigarette sales didn't discuss this particular pair, put on quiz for tomorrow Unneccessary complexity, misunderstandings 1992 American Jewish Committee [NY Times July 8, 1994] Does it seem possible or does it seem impossible to you that the Nazi extermination of the Jews never happened? (22% possible) Does it seem possible to you that the Nazi extermination of the Jews never happened, or do you feel certain that it happened? (1% possible) -------------- only got this far -------------------- "do you own stock?" cartoon Asking the uninformed will see an example in a video 1975 Public Affairs Act [didn't exist] (page 35) in 1978 1/3 expressed opinion in 1995 nearly 1/2 expressed opinion with leading political bias, 53% expressed opinion and tended to go with political leanings Ordering of questions, additional information peer pressure example (34) Open/closed questions museum example Defining your terms adolescent sex: increasing or decreasing? (page 37) unemployment happiness (happiness newpaper article) "The Truth but not the Whole Truth" Friday, January 7 Topic: Sampling Topic: Observation and Experimentation Act: Read: Utts 4 Read: Utts 5 Due: HW #1 @ hw01.shtml Vocab: Vocab: observational study, experiment, meta-analysis, treatment, Vocab: explanatory variable, outcome variable (response variable), Vocab: unit, population, sample, sampling frame, sample survey, census, Vocab: margin of error, "1 Over Root n Rule", Vocab: simple random sampling, stratified random sampling, Vocab: cluster sampling, systematic sampling, random digit dialing, Vocab: multi-stage sampling, convenience sample, response rate To conduct a study properly 1) get a representative sample 2) get a large enough sample 3) decide between observational study and experiment Basic categories of studies experiment key: treatment observational study meta-analysis case study (popular in media -- clip from ABC news?) Sampling terminology: unit, population, sample, sampling frame, sample survey, census, margin of error sampling vs. census: samples are often possible, faster, accurate Sampling Methods SRS stratified random sampling cluster sampling systematics sampling random-digit dialing multistage sampling Sampling difficulties wrong sampling frame not reaching selected individuals low response rate volunteer sample haphazard or convenience sample Literary Digest poll (1936) Alf Landon predicted to get 3-2 victory volunteer response to sample from poor frame George Gallup Experiment terminology over weekend: get pulse rate several times and bring numbers on monday