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Test 4 - test04_s

# Test 4 - test04_s - El ent em ary St i i at st cs Fal,2010...

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Elem entary Statistics Fall,2010 Test4 1:30 pm ,SW C D-134 Nam e:AnswerKey D r.D .P.Story Instructions:(100points)Solve each problem . A lldecim alnum bers— unless otherw ise specifed— should be rounded to ±ourdeci malplaces. (3 pts ea. ) 1.True/False.Enter ‘T’±orTrueand ‘F’±or False i ntheblank spaces provided. (a) T I±you rejectthe nullhypothesis,you can support the altern ate h yp o th esis. (b) F Thesignifcancelevel ,isthemaxi mum allow abletypeII error p erm itted . (c) F Given that H 0 :μ = 100,H a :μ = 100,and P = 0.0461,atsignifcance level = 0.01 wecanrejectthe nullhypothesis. (d) T I±aseto±paired d ata (x ,y ) h as a n egative correlation,then as x tends to be larger and larger,th e corresp on d ing value o±y tendsto be sm aller and sm aller. ShortResponses (25 points). (5 pts ) 2.A cardealer claim s that at least24% o±its new custom ers willreturn to buy theirnextcar.Letp be the true population proportion o±new custom ers thatw illreturn to buy a new car. (a)Based on the clai mo ±t h ed e a ler,setup the hypothesisusing the rules introduced by the text: H 0 :p0 . 24 H a :p < 0 . 24 (b)W rite sentences describing,inlaym en’sterm s,typeIandtypeIIerrors±orthistesto±hypothesis. typeIerror: Rejectthe dealer’sclai m,whenitistrue typ e IIerror: Acceptthe dealer’sclai mwh e nitis±alse pts ) 3.Nin e stu d en ts to o k th e SA T . T h eir scores are listed below . Later on,they took a testpreparation course and retook the SA T.Their new scores are listed below .How w oul dyoutesttheclai mt h a t th e test p rep arati onhadnoe ectontheir scores. U se = 0.05.Assum e thatthe distribution is norm allydistributed. Student 1234567 8 9 Score be±ore course,x 1 720 860 850 880 860 710 850 1200 950 Score a±ter course,x 2 740 860 840 920 890 720 840 1240 970 Write a sh ort p aragrap h d iscussing how to analyze thisproblem .G ive enough in±orm ation to show thatyou know the correctm ethod to use.Finish o by speci±ying whatcalculator testyou w ould apply,±or exam ple 1:ZTEST.Do notactually per±orm the testo±hypothesis,n o calculations ±or this problem . Solution: Thisisatwo-sam plepaired t-test. W e d ef n e d = x 1 ²x 2 ,and per±orm 2:TTEST on the resu ltan t o n e-sam pledata.Todothis,frst enter the d -data into a list,then apply 2:TTEST.

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STA2023/T4
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Test 4 - test04_s - El ent em ary St i i at st cs Fal,2010...

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