One-WayANOVAs

PARTI:

1.Ifyouwantedtocomparemeansfromseveraldifferentgroups,whywoulditbe

problematictoperformmultiplet-testsusing.05foralpha?Whyisrunningan

ANOVA(alpha=.05)preferable?

2) Aresearcheristestingifdifferentstrainsofmicearebetterlearnersthanothers. Shetrainsmicefromthreedifferentstrains(Strain1,Strain2,andStrain3)onamazeandrecordsthenumberoferrors(wrongturns)eachmousemakes

Strain 1 Strain 2 Strain 3

Mean # of errors 13 8.5 7

n 7 7 7

b.CompletetheANOVAtablebelowusingtheinformationontheprevious

page.

SS df MS F

Between 136.5 _____ ______ ______

Within 180 ______ _______

Total _____ ______

FindFcritfor(=.05).DowerejectH0?

c.Compute2asameasureofeffectsize.

d.Shouldyourunpost-hoctests?Explainwhyorwhynot.

e.Ifyouanswered'yes'toPartd,performposthocsusingTukey'sHSD.

Indicatewhichcomparisonsarestatisticallydifferentandwhicharenot.

f.WriteupallofyourresultsfromPartsb-einstandardformat(see

samplepostedonCanvasforanexample).

PART II

1.ThefollowingincompleteOne-FactorANOVAtablecomesfromastudywithfourgroupsandn=

15ineachgroup

SS df MS

Between 81 ____ _____ F=_____

within ____ _____ _____

total 249 ______

Statisticallysignificantatthe.05level?_______________

2.ThefollowingincompleteOne-FactorANOVAtablecomesfromastudywiththreegroupsandn=

12ineachgroup.(Hint:completethedfcolumnfirst.)

SS df MS

Between ____ ____ 9 F=_____

Within ____ _____ ____

Total 117 _____

Statisticallysignificantatthe.05level?_______________

3.ThefollowingincompleteOne-FactorANOVAtablecomesfromastudywiththreegroupsandn=

10ineachgroup.(Hint:completethedfcolumnfirst.)

SS df MS

Between ____ ____ 15 F=7.5

Within ____ ______ ____

Total _____ ______

Statisticallysignificantatthe.05level?_______________