stat200ch3_extraslides - Pm association = Causaflon 7 - An...

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Unformatted text preview: Pm association = Causaflon 7 - An obseruo‘ricm .s’mdy never proves a cause—ond— efiecr relationship because +here may be COnFOunding -Fac'rors E 1:. g. 53 5: 922g: patien’rs healthy wqu heart individuals dnseaae % .Srnokers: higher lower (Smoking is associafed coffin Hag . chance of having hearf' disease) CoflfDundmg / varioifms % heavy higher lower drinkers 3’3 amine {any die The higher chance oF getfing heari- diseose Can be, amused by having high aicohol consumption or 150m; diets. The 2 Variables associafed +0 we, oufcome, are conFOmnding variables. h igher [ow er (103) 5 - :‘n an experiment a cause~ondv eHecr refafionship can be esi'abhlshed e-a 2§ s 2 g 2 g i S receive 1’5 random receive new-dug, “55‘3"WH?exian9 drug RCSPOHSEI r Lo‘Reduc-hon more [855 _ 1" H0015 sigmficam SEgni-Flcanr pressure. “he dWQ +ype is GSSOCEQfed win ‘H'IE amount dropped in blood prefiumj A955 about Hui. Jami. Gender CcmPDSI-Hon about m rm Having diabe+e5 about Hug sank», we Com Confiden’riy say *5th The; new drug is more effecfiue «rhan Hoe exisfing drugJ bur we ac’rually need to see CL “suFfiCienHy Iarge” diFference {m response. beFore we, Can make. 1106 above conclusion. made Is +he diFFerence real? e‘q. Experimenf comparing the“webrbasefll group to the fitmditionalvgroup median final 3'7sz web — based :5 a; traditional 65 °/., 7‘ [0% diFFeyeBncev Is HHS dIFFereche r‘emfy due +0 Hie diFFerence m mode of insfrucfion? Or i541: J'qu a random Fluctuafim)? Scenario 1 Scanan‘o 2 final gmdg final grade 15 65 direerem g; 22%251193 diam tradflbml “’eb' tmdiu'on on web- based based diFFertnca in madiam dfiFferena. in median fi‘na'. grade is Small final grade is age compared to the Spread small compared to or"- me grades the spread OF «the grade: II F. 375%rence in the FESPOnse variabie baf-szEn -':'n€ wnfm. grcup and of‘nEr’ Stream/hem groupis) Can be The resuft of- (a) Chance VGrEatJOn a, true e-FFed C? the treaTmEn'f' being tested I \ t2, scenario 1.: the obsewed diFFerence r5 likew to 19?, due {:0 chance the observed d EFFerence Seems largei No+ liken; +0 have oceurred due +t> Chance! ,r We diFFer’ence is said {-0 be STm‘fSTTCALL‘f SIGNIFICANT Scenario 2 - ...
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This note was uploaded on 10/21/2010 for the course STATISTICS Stat 200 taught by Professor Eee during the Spring '10 term at The University of British Columbia.

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stat200ch3_extraslides - Pm association = Causaflon 7 - An...

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