Question #1 In1990, 5.8% ofjob applicants whowere testedfor drugsfailed thetest. A randomsample

Question #1 In1990, 5.8% ofjob applicants whowere testedfor drugsfailed thetest. A randomsample of1440currentjobapplicantsresults in61failures (basedloosely on datafromthe AmericanManagementAssociation).   Attheα=0.01significancelevel, testthebelowcl

Question #1

In1990, 5.8% ofjob applicants whowere testedfor drugsfailed thetest.

A randomsample of1440currentjobapplicantsresults in61failures (basedloosely ondatafromthe AmericanManagementAssociation).

 

Attheα=0.01significancelevel, testthebelowclaim(i.e.,thatthefailure rateis now lower)

 

HO:p = 0.058

HA:p < 0.058

 

  1. a) Is thisanuppertail,lower tail,or two-tailtest?(5points)
  2. b) Are we testing meansor proportions?(5points)

c)Statethe rule ofrejection(in termsofp-valueandlevel ofsignificance) (5points)

  1. d) Findthep-value(5points)
  2. e) Shouldyourejector notreject HO?(5points)
  3. f) Does theresult suggestthatfewer job applicantsnowuse drugs?(5 points)

 

Researchers studyinginfantheadcircumferences (incentimeters)wish totestifthemeanheadcircumference differsfromthehistorical mean of34.5cm.Theresearchers obtainasample of17infantswithameanheadcircumferenceof34.16cmanda standard deviationof0.58cm.

 

Attheα=0.05significancelevel, testtheclaim

 

HO:µ=34.5

HA:µ≠ 34.5

 

  1. a) Is thisanuppertail,lower tail,or two-tailtest?(5points)
  2. b) Are we testing meansor proportions?(5points)

c)Statetherule ofrejection(in termsof p-valueandlevel ofsignificance) (5points)

  1. d) Findthep-value(5points)
  2. e) Shouldyourejector notreject HO?(5points)
  3. f) Does theresult suggestthatthemeanheadcircumferencediffersfrom34.5cm? (5points)

 

 

 

Question #3

Performthefollowing hypothesistest onthepaired data below:

 

HO:µd=0(Pleaserecallthat µdis read~and alsoknown as ~Mu-sub-d)HA:µd≠0Test atα=0.05

 

Before 30 72 97 59 61 57 57 89 92
After 57 68 98 62 67 71 68 96 98

 

 

 

  1. a) Isthisanuppertail,lower tail,or two-tailtest?(5points)
  2. b) Are we testing meansor proportions? (5points)

c)Statetherule ofrejection(in termsofp-valueandlevel ofsignificance) (5points)

  1. d) Findthep-value(5points)
  2. e) Shouldyourejector notreject HO?(5points)
  3. f) DothedataprovidesufficientevidencetosuggesttheAfter scores are indeed higher?Whyor whynot?(5points)

 

Note:Becausetheabove isatwo-tailtest,rejection ofHo aloneisnot a  sufficient reason.Hint: What elsedidyou observe among the sampleresults?

 

Thebelowsampledatarepresentsthecost of9name-branddrugsandtheir corresponding genericequivalent.(UseNameBrandasSample1)

 

Name

Brand

120 150 135 140 160 175 140 120 165
Generic

Brand

99 135 130 119 139 150 129 109 160

 

 

 

  1. a) Computeatwo-sided 90%confidenceInterval estimatefor µd.(5points)

 

 

  1. b) Basedonyour interval, canyousafelyconcludethatgenerics arelessexpensive thannamebrand?Whyorwhynot?(5 points)
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