Methodofcalculatingsamplevariancedenominatornumerators2Sourceofvariationd.f.sumofs uaresmean s uares~/w~f3-1~Lf1.'-t39.f-2_XIfthe alternative hypothesis is true, that will tend to make the "Between sample" variance largerthan the "Within sample" variance.But we also realize that could happenjustby chanceofsampling,ifthe null hypothesis were true.How dowedecide which has more likely happened here?The F-statisticiscalculatedasthe ratiooftwo variances:F-observed=BetweensamplevarianceWithinsamplevariance11

##### We have textbook solutions for you!

**The document you are viewing contains questions related to this textbook.**

Expert Verified

Oops!! !I left out an important aspectofhow this experiment was conductedAfterthesampleof15pastordershadbeenselected,5differentjobberswererecruitedtohelpwiththeexperiment.Threeorderswererandomlyassignedtoeachjobber,andeachjobberrandomlyassignedhis/herorderstothethreedifferentprocedures.So the layoutofthe study really looked like:Procedure123HarryEthelArthurRandyTomThe numerical summary results were correctasoriginally provided How will this newinformation affect the ANOVA table?Sourceofvariationd.f.sumofsquaresmean squares~s~{~L.'l,C(.5:>~Z.-~~1~(l5-(.-:,l1&(~-tf'33Xf)12

Example:Anoilcompanyisattemptingtodevelopareasonablypricedgasolinethatwilldeliverimprovedgasmileage.Aspartofthedevelopmentprocess,thecompanywantstocomparetheeffectofthreetypesofgasoline(A,BrC)ongasmileage.Fortestingpurposes,allthecarsusedwillbeaparticularpopularmid-sizemodelcalledtheGopher.•Arandomsampleof15Gophersisobtainedfromthemanufacturer,and5Gophersarerandomlyassignedtoeachofthegasolinetypes.•EachrandomlyselectedGopheristestdrivenusingtheappropriategasolinetype(treatment}undernormalconditionsforaspecifieddistancerandthegasmileageforeachtestdriveismeasured.Refertothedatafile"GopherGas.mtw"SSMSFPSourceDFgastype2Error1217.0498.525~,12.74o.oo1Vtvbr~8.028~...:..66__9_-------.o:~,lA~Total1425.077....r'<-s=0.8179R-Sq67.99%R-Sq(adj)=62.65%Level123N555Mean34.92036.56033.980StDev0.7660.8500.835PooledStDev0.818Individual95%CisForMeanBasedonPooledStDev---+---------+---------+---------+------(------*------)(------*-----)(-----*------)---+---------+---------+---------+------33.634.836. 037.213

Wecan reject the null hypothesis,andwe conclude that not all the gasoline types have the samepopulation mean.Buthow different is AfromB? AfromC?BfromC?Weknow how to build a confidence intervalforthe difference between population means:Supposewedid construct those different confidence intervals, each with 95% confidence. Howconfident couldwebe thatALL3ofthe intervals provide correct claims?A methodology for constructing all the possible confidence intervalsfor difference between2population means, with an associated "familyconfidence coefficient" that all the constructed intervals are correctstatements.

Upload your study docs or become a

Course Hero member to access this document

Upload your study docs or become a

Course Hero member to access this document

End of preview. Want to read all 103 pages?

Upload your study docs or become a

Course Hero member to access this document

Term

Spring

Professor

Ahrens,MarkE

Tags

xbar