Soc201\tAssignment\t#5 \"Comparing\tProportions\t&\tMeans\tof\tTwo\tGroups\" This\tassignment\trequires\tyou\tto\twrite\tout\tyour\tanswers\tthe\toldfashion\tway\t-\tlegibly\tand\ton\tpaper\t-\tand it must be handed in - in person and before class begins on November 22nd, 2016. Once again, I encourage\tyou\tto\tsubmit\twhatever\tyou've\tcompleted\ton\tor\tbefore\tthe\tdue\tdate.\tMy\tTA\tand\tI\tare\teager\tto assist\tyou\twith\tthis\tassignment\tif\tyou\temail\tus\tin\tadvance\tto\tset\tup\tan\tappointment\tduring\t(or\toutside\tof) our\tweekly\toffice\thours. 1. Normal\tAssumption:\tThe\tmethods\tof\tthis\tsection\tmake\tthe\tassumption\tof\ta\tnormal\tpopulation\tdistribution. Why\tdo\tyou\tthink\tthis\tis\tmore\trelevant\tfor\tsmall\tsamples\tthan\tfor\tlarge\tsamples? 2. "Freshman\t15"\ta\tmyth?: The\t"freshman\t15"\tis\tthe\tname\tof\ta\tcommon\tbelief\tthat\tcollege\tstudents,\tparticularly women,\tgain\tan\taverage\tof\t15\tpounds\tduring\ttheir\tfirst\tyear\tof\tcollege. In\tone\tstudy\tof\t110\tfemale\tfirstyear college\tstudents\t(Psychology\tof\tWomen\tQuarterly,\tvol\t17,\tpp.119126,\t1993),\tthe\tmean\tweight\twas\t130.6 pounds\tat\tthe\tbeginning\tof\tthe\tstudy\tand\t131.4\tpounds\tsix\tmonths\tlater. The\tstandard\tdeviation\twas\tabout\t20 pounds\tat\teach\ttime. a. Estimate\tthe\tchange\tin\tthe\tmean\tweight\tover\tthis\tsixmonth\tperiod. b. Is\tthis\tsufficient\tinformation\tto\tfind\ta\tconfidence\tinterval\tor\tconduct\tat\testimate\tabout\tthe change\tin\tthe mean\tover\tsix\tmonths? If\tnot\twhat\telse\tdo\tyou\tneed\tto\tknow? 3. President's\tpopularity: Last\tmonth\ta\trandom\tsample\tof\t1000\tsubjects\twere\tinterviewed\tand\tasked\twhether they\tthink\tthe\tpresident\tis\tdoing\ta\tgood\tjob. This\tmonth\tthe\tsame\tsubjects\twere\tasked\tthis\tagain. The\tresults are:\t450\tsaid\t"yes"\teach\ttime,\t450\tsaid\t"no"\teach\ttime\t60\tsaid\t"yes"\ton\tthe\tfirst\tsurvey\tand\t"no"\ton\tthe\tsecond survey,\tand\t40\tsaid\t"no"\ton\tthe\tfirst\tsurvey\tand\t"yes"\ton\tthe\tsecond\tsurvey. a. Form\ta\tcontingency\ttable\tshowing\tthese\tresults. b. Estimate\tthe\tproportion\tgiven\ta\tfavorable\trating\t(i)\tlast\tmonth\tand\t(ii)\tthis\tmonth. 4. Pick\tthe\tmethod:\tSteven\tSolomon,\tthe\towner\tof\tLeonardo's\tItalian\tRestaurant,\twonders\twhether redesigned\tmenus\twill\tincrease,\ton\tthe\taverage,\tthe\tamount\tthat\tcustomers\tspend\tin\tthe\trestaurant. For\tthe\tfollowing\tscenarios\tpick\ta\tstatistical\tmethod\tfrom\tthis\tchapter\tthat\twould\tbe\tappropriate\tfor analyzing\tthe\tdata,\tindicating\twhether\tthe\tsamples\tare\tindependent\tor\tdependent,\twhich\tparameter\tis relevant\tand\twhat\tinference\tmethod\tyou\twould\tuse: a. Solomon\trecords\tthe\tmean\tsales\tthe\tweek\tbefore\tthe\tchange\tand\tthe\tweek\tafter\tthe\tchange\tand then\twonders\twhether\tthe\tdifference\tis\t"statistically\tsignificant." b. Solomon\trandomly\tsamples\t100\tpeople\tand\tshows\tthem\teach\tboth\tmenus,\tasking\tthem\tto\tgive\ta rating\tbetween\t0\tand\t10\tfor\teach\tmenu. c. Solomon\trandomly\tsamples\t100\tpeople\tand\tshows\tthem\teach\tboth\tmenus,\tasking\tthem\tto\tgive\tan overall\trating\tof\t"positive"\tor\t"negative"\tto\teach\tmenu. d. Solomon\trandomly\tsamples\t100\tpeople\tand\trandomly\tseparates\tthem\tinto\ttwo\tgroups\tof\t50\teach. He\tasks\tthose\tin\tgroup\t1\tto\tgive\ta\trating\tto\tthe\told\tmenu\tand\tthose\tin\tgroup\t2\tto\tgive\ta\trating\tto\tthe new\tmenu,\tusing\ta\t0\tto\t10\trating\tscale. 5. Females\tor\tmales\thave\tmore\tclose\tfriends?: A\trecent\tGSS\treported\tthat\tthe\t486\tfemales\thad\ta mean\tof\t8.3\tclose\tfriends\t(s\t=15.6)\tand\tthe\t354\tmales\thad\ta\tmean\tof\t8.9\tclose\tfriends\t(s\t=\t15.5). a. Estimate\tthe\tdifference\tbetween\tthe\tpopulation\tmeans\tfor\tmales\tand\tfemales. b. The\t95%\tconfidence\tinterval\tfor\tthe\tdifference\tbetween\tthe\tpopulation\tmeans\tis\t0.6\t\t2.1. Interpret. c. For\teach\tgender,\tdoes\tit\tseem\tlike\tthe\tdistribution\tof\tnumber\tof\tclose\tfriends\tis\tnormal? Why? How\tdoes\tthat\taffect\tthe\tvalidity\tof\tthe\tconfidence\tinterval\tin\t(b)? 6. Drink\ttea:\tA\tstudy\tfollowed\tpatients\tfor\tfour\tyears\tafter\tthey\thad\ta\theart\tattack\t(K.\tMukamal\tet\tal., Circulation,\tvol.\t105,\tpp.24762481,\t2002). Patients\twere\tinterviewed\tabout\ttheir\tweekly\tcaffeinated tea\tconsumption\tduring\tthe\tyear\tbefore\tthe\theart\tattack. The\trelative\trisk\tof\tanother\theart\tattack during\tthe\tstudy\tperiod\tfor\tthose\twho\treported\tdrinking\tat\tleast\t14\tcups\ta\tweek,\tcompared\tto\tthose who\treported\tnot\tdrinking\ttea,\twas\t0.56,\twith\ta\t95%\tconfidence\tinterval\tof\t0.37\tto\t0.84. a. Interpret\tthe\tconfidence\tinterval\tfor\tthe\tpopulation\trelative\trisk. b. According\tto\tthese\tresults,\tcan\twe\tconclude\tthat\tin\ta\tcorresponding\tpopulation,\ttea\tdrinking reduces\tthe\tchance\tof\tanother\theart\tattack? Explain. 7. Prison\trates:\tThe\tU.S.\tDepartment\tof\tJustice\t(ww.ojp.usdoj.gov/bjs)\tgives\tincarceration\trates\tin\tthe nation's\tprisons\tfor\tvarious\tgroups. a. In\t2006\tthe\tincarceration\trate\twas\t1\tper\t109\tmale\tresidents\tand\t1\tper\t1563\tfemale\tresidents. Find the\tratio\tof\tincarceration\trates\tand\tinterpret. b. In\t2006\tthe\tincarceration\trate\twas\t1693\tper\t100,000\tblack\tresidents\tand\t252\tper\t100,000 white residents. Find\tthe\tratio\tof\tincarceration\trates\tand\tinterpret. 8. Seat\tbelts\thelp?: For\tautomobile\taccidents\tin\ta\trecent\tyear\tin\tMaine,\tinjuries\toccurred\tto\t3865\tof 30,902\tsubjects\tnot\twearing\tseat\tbelts\tand\tto\t2409\tof\t37,792\tsubjects\twearing\tseat\tbelts. Find\tand interpret\tthe\trelative\trisk\tfor\tthese\tdata. 9. Obesity\tand\tearnings:\tAn\tAP\tstory\t(April\t9,2005)\twith\theadline\tStudy:\tAttractive\tPeople\tMake\tMore stated\tthat\t"A\tstudy\tconcerning\tweight\tshowed\tthat\twomen\twho\twere\tobese\tearned\t17\tpercent\tlower wages\tthan\twomen\tof\taverage\tweight.\" a. Identify\tthe\ttwo\tvariables\tstated\tto\thave\tan\tassociation. b. Identify\ta\tcontrol\tvariable\tthat\tmight\texplain\tpart\tor\tall\tof\tthis\tassociation. If\tyou\thad\tthe\toriginal data\tincluding\tdata\ton\tthat\tcontrol\tvariable,\thow\tcould\tyou\tcheck\twhether\tthe\tcontrol\tvariable does\texplain\tthe\tassociation? 10.\tAfford\tfood?: True\tor\tfalse? A\t2003\tsurvey\tby\tthe\tPew\tResearch\tCenter\tasked\twhether\tthere\thave been\ttimes\tin\tthe\tpast\tyear\tthe\trespondent\thas\tbeen\tunable\tto\tafford\tfood. Of\tadvanced\teconomies, the\tcountry\twith\tthe\thighest\tresponse\twas\tthe\tUnited\tStates,\t15%.\tWorldwide\tthe\thighest\tresponse was\tin\tAngola,\t86%. Because\tthe\tsame\tquestion\twas\tasked\tin\tboth\tcountries,\tthe\tsamples\tare dependent