04:13:44 Total = 28 slides1Sociology 201:Social Research Design13. Sampling Examples04:13:44 Total = 28 slides2Preview•Review Chap 7 Workbook Assignments•Sampling examples–Medical school faculty members–Episcopal Churchwomen–University students–Oakland, CA households•Mid-Term Review Sheet04:13:44 Total = 28 slides37.1: Simple Random Sample•Select random numbers from table •Those people are in the sample04:13:44 Total = 28 slides47.2: Stratified Systematic Sample•Stratify list by gender•Sampling interval is 72/10 = 7.2•Pick random number between 1 and 7•Take every 7th name afterward04:13:44 Total = 28 slides5Examples of Sample Designs04:13:44 Total = 28 slides6Medical school faculty in Medicine and Pediatrics•84 4-year medical colleges at time of study•Population and sample size–Estimated 12,000 faculty in Medicine and Pediatrics–Figured 2000 (1/6) would be enough04:13:44 Total = 28 slides7Medical School Faculty•Selecting schools•Geographical stratification•Random start 1-6•Picked 14 schools•Not all deans cooperated–(Project diary to follow)04:13:44 Total = 28 slides8August 16: Letters sent to the 14 medical school deans, in-troducing the project and requesting permissionto survey their faculties.August 23: School A replied, approving the study.August 30: Schools B and C approved the study; School Drefused.August 31: Selected School D' as replacement and wrote todean.September 13: School E approved the study.September 20: School F approved the study.September 21: Sent follow-up letters to nonresponding deans.October 7:Called nonresponding deans; assured that an-swers would follow.October 12: Schools G and H refused.04:13:44 Total = 28 slides9October 13: Selected Schools G' and H' as replacements and wrote to deans.October 14: School I approved study.October 15: Called School E requesting faculty list not yet received.October 20: School I refused; selected School il as replacement and wrote to dean. Wrote to School I requesting faculty list.October 22: School K refused; selected School K' as replacement and wrote to dean.October 27: School W approved the study.November 2: School D' refused.November 8: Received faculty list from School E.November 19: School G' approved the study.November 24: School K' approved the study-04:13:44 Total = 28 slides10Episcopal Churchwomen•Wanted 500 respondents–25 churches with 20 women each PPS–N = 200,000 SI = 800004:13:44 Total = 28 slides11Church Selection•Church Size From To Picks•Church A 5,000 1 5,000 4,000•Church B 2,000 5,001 7,000•Church C 3,000 7,001 10,000•Church D 8,000 10,001 18,000 12,000•Church E 1,000 18,001 19,000•Church F 4,000 19,001 23,000 20,000•Church G 6,000 23,001 29,000•etc.04:13:44 Total = 28 slides12Episcopal Churchwomen•Sampling within churches•Discuss bad estimates of church size•Automatic weighting04:13:44 Total = 28 slides13Sampling University Students•Survey population and sampling frame–Magnetic registration tape–It contained too many people•Survey population defined as –15,225 day program degree candidates registered for the Fall semester on the Manoa campus--both undergraduate and graduate, American and foreign•DISCUSSION: What decisions would we have to make at Chapman?04:13:44 Total = 28 slides14Sample selection program•Stratified tape by class; could have done more•Chose n of 1100•Systematic selection of 1/1404:13:44 Total = 28 slides15Printed 6 labels per student1st envelope1st postcard2nd envelope2nd postcard3rd envelope3rd postcard12654304:13:44 Total = 28 slides16Sample modification•Questionnaires and postage too expensive•Systematically threw away 1/3 of labels04:13:44 Total = 28 slides17Processing of returns•Postcards began coming in•Throw away those mailing labels•Wrong order!•Reorganized the labels04:13:44 Total = 28 slides18Multi-stage cluster sample•Oakland, CA•Model Cities Program•Unemployment 6% or more– Risk of underestimating–Create sample design04:13:44 Total = 28 slides19Seven areas of city04:13:44 Total = 28 slides20Overall Design•500 households from each area–n of 3500 in city•100 blocks with 5 hh each•2 blocks from each of 50 homogeneous strata04:13:44 Total = 28 slides21Data for Stratification•1960 census data•Building and demolition permits04:13:44 Total = 28 slides22Stratification Variables•Growth since census•Percent nonwhite•Percent renter-occupied•Percent deteriorating•Value of structures –rent or assessment•Process of stratification04:13:44 Total = 28 slides23Selecting the households•Listing the blocks•Household selection within blocks•Weighting the responding households04:13:44 Total = 28 slides24Selecting HouseholdsPick sample of blocksList householdsSample from listsAnother view04:13:44 Total = 28 slides25Review Sheet for Mid-term04:13:44 Total = 28 slides26Next Time•Review for Mid-term•Review Chapters