Statistic Final for maths 225N QUESTIONS WITH CORRECT ANSWERS latest 2020-2021(graded A)

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1/1POINTS Afitnesscenterclaimsthathemeanamountoftimethatapersonspendsathegym pervisitis33 minutes.Identifythenulhypothesis,H0,andthealternative hypothesis,Ha,intermsoftheparameterμ. H0:μ�... �33;Ha:μ=33 H0:μ=33;Ha:μ≠33 H0:μ≥33;Ha:μ<33 H0:μ≤33;Ha:μ>33 AnswerExplanation Corectanswer: H0:μ=33;Ha:μ≠33 Letheparameterμ beusedtorepresenthemean.Thenulhypothesisisalways statedwithsomeform ofequality:equal(=),greaterthanorequalto(≥),orlessthan orequalto(≤).Therefore,inthiscase,thenulhypothesisH0 isμ=33.The alternativehypothesisiscontradictorytothenulhypothesis,soHa isμ≠33. QUESTION2 1/1POINTS Theanswerchoicesbelowrepresentdifferenthypothesistests.Whichofthechoices areright-tailedtests?Selectalcorrectanswers. • H0:X≥17.1,Ha:X<17.1 • • H0:X=14.4,Ha:X≠14.4 • • H0:X≤3.8,Ha:X>3.8 • • H0:X≤7.4,Ha:X>7.4 • • H0:X=3.3,Ha:X≠3.3 • AnswerExplanation Corectanswer: Remembertheformsofthehypothesistests. • Right-tailed:H0:X≤X0,Ha:X>X0. • Left-tailed:H0:X≥X0,Ha:X<X0. • Two-tailed:H0:X=X0,Ha:X≠X0. Sointhiscase,theright-tailedtestsare: • H0:X≤7.4,Ha:X>7.4 • H0:X≤3.8,Ha:X>3.8 QUESTION3 0/1POINTS FindtheType Ierrorgiventhathenulhypothesis,H0,is:abuildinginspectorclaims thatnomorethan15% ofstructuresinthecountywerebuiltwithoutpermits. Thebuildinginspectorthinksthatnomorethan15% ofthestructuresinthecounty werebuiltwithoutpermitswhen,infact,nomorethan15% ofthestructuresrealywere builtwithoutpermits. Thebuildinginspectorthinksthatmorethan15% ofthestructuresinthecountywere builtwithoutpermitswhen,infact,morethan15% ofthestructuresrealywerebuilt withoutpermits. Thebuildinginspectorthinksthatmorethan15% ofthestructuresinthecountywere builtwithoutpermitswhen,infact,atmost15% ofthestructureswerebuiltwithout permits. Thebuildinginspectorthinksthatnomorethan15% ofthestructuresinthecounty werebuiltwithoutpermitswhen,infact,morethan15% ofthestructureswerebuilt withoutpermits. AnswerExplanation Corectanswer: AType Ierroristhedecisionnotorejecthenulhypothesiswhen,infact,itisfalse.In thiscase,theType Ierroriswhenthebuildinginspectorthinksthatnomore than15% ofthestructureswerebuiltwithoutpermitswhen,infact,more than15% ofthestructureswerebuiltwithoutpermits. Youranswer: Content attribution- Opens a dialog QUESTION4 1/1POINTS Sup oseachefclaimsthathermeatbalweightislessthan4 ounces,onaverage. Severalofhercustomersdonotbelieveher,sothechefdecidestodoahypothesistest, ata10% significancelevel,topersuadethem.Sheco ks14 meatbals.Themean weightofthesamplemeatbalsis3.7 ounces.Thechefknowsfrom experiencethathe standarddeviationforhermeatbalweightis0.5 ounces. • H0:μ≥4;Ha:μ<4 • α=0.1 (significancelevel) Whatistheteststatistic(z-score)ofthisone-meanhypothesistest,roundedtotwo decimalplaces? AnswerExplanation Corectanswers: Thehypotheseswerechosen,andthesignificancelevelwasdecidedon,sothenext stepinhypothesistestingistocomputetheteststatistic.Inthisscenario,thesample meanweight,x¯=3.7.Thesamplethechefusesis14 meatbals,son=14.She knowsthestandarddeviationofthemeatbals,σ=0.5.Lastly,thechefiscomparing thepopulationmeanweighto4 ounces.So,thisvalue(foundinthenulandalternative hypotheses)isμ0.Nowwewilsubstitutethevaluesintotheformulatocomputethe teststatistic: z0=x¯−μ0σn√=3.7−40.514√≈−0.30.134≈−2.24 So,theteststatisticforthishypothesistestisz0=−2.24. QUESTION5 1/1POINTS Whatisthep-valueofaright-tailedone-meanhypothesistest,withateststatistic ofz0=1.74?(Donotroundyouranswer;computeyouranswerusingavaluefrom the tablebelow.) z1.51.61.71.81.90.000.9330.9450.9550.9640.9710.010.9340. 9460.9560.9650.9720.020.9360.9470.9570.9660.9730.030.9 370.9480.9580.9660.9730.040.9380.9490.9590.9670.9740.0 50.9390.9510.9600.9680.9740.060.9410.9520.9610.9690.97 50.070.9420.9530.9620.9690.9760.080.9430.9540.9620.970 .9760.090.9440.9540.9630.9710.977 AnswerExplanation Corectanswers: Thep-valueistheprobabilityofanobservedvalueofz=1.74 orgreaterifthenul hypothesisistrue,becausethishypothesistestisright-tailed.Thisprobabilityisequalto theareaundertheStandardNormalcurvetotherightofz=1.74. ..................................................................................CONTINUED............................................................................................ [Show More]

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