质量管理 第4版 教案 12-QM Homework Assignments for students

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QualityManagement

ByDr.MaFengcai

Take-HomeProblemSolvingandEssayQuestions

StudentName:

Problem#1-ToolsofTQM

<Problem1-A>

DevelopaParetoanalysisofthefollowingcausesofpoorgradesonanexam:

Reasonforpoorgrade

Frequency

Insufficienttimetocomplete

Latearrivaltoexam

Difficultyunderstandingmaterial

Insufficientpreparationtime

Studiedwrongmaterial

Distractionsinexamroom

Calculatorbatteriesdiedduringexam

Feltillduringexam

16

7

26

2

2

10

1

4

<Problem1-B>

MaryBethMarrs,themanagerofanapartmentcomplex,feelsoverwhelmedbythenumberofcomplaintssheisreceiving.Belowisthechecksheetshehaskeptforthelast12weeks.DevelopaParetochartusingthisinformation.Whatrecommendationswouldmake?

Week

Grounds

Parking/Drives

Pool

TenantIssues

Electrical/Plumbing

1

2

3

4

5

6

7

8

9

10

11

12

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√

Problem#2-Reliability(SeriesReliabilityandRedundancy)

<Problem2-A>

TheNationalBankofGreeley,Colorado,processesloanapplicationsthroughthreeclerkssetupinseries:

.90

.80

.99

R1

R2

R3

RS

<Questions>

Woulditbebettertoincreasetheworstclerk’sreliabilityfrom.8to.81orthebestclerk’sreliabilityfrom.99to1?

Isitpossibletoachieve90%reliabilitybyfocusingononlyoneofthethreeclerks?

<Problem2-B>

TheNationalBankisdisturbedthatitsloanapplicationsoftheloanprocesspresentedinProblem2-A.

<Questions>

Ifoneadditionalclerkwereavailablewhichwouldbethebestplacetoaddthisclerk?

Whatistheminimumnumberoftotalclerksthatneedtobeaddedinordertoachieveasystemreliabilityof99%?

Problem#3-StatisticalProcessControl(SPC)

<Problem3-A>

Computerupgradeshaveanominaltimeof80minutes.Samplesoffiveobservationseachhavebeentaken,andtheresultsareaslisted.Determineupperandlowercontrollimitsformeanandrangecharts,anddecideiftheprocessisincontrol.

Sample

1

79.2

78.8

80.0

78.4

81.0

11

80.2

81.1

79.8

78.9

79.3

2

80.5

78.7

81.0

80.4

80.1

12

78.9

79.2

79.0

80.4

80.3

3

79.6

79.6

80.4

80.3

80.8

13

80.2

79.6

78.7

80.5

79.3

4

78.9

79.4

79.7

79.4

80.6

14

79.4

78.8

80.4

80.6

80.0

5

80.5

79.6

80.4

80.8

78.8

15

81.0

80.7

79.5

80.6

79.7

6

79.7

80.6

80.5

80.0

81.1

16

80.2

79.8

79.3

80.6

81.0

7

81.0

80.6

79.5

78.6

79.0

17

79.5

80.6

81.0

80.4

79.9

8

81.2

80.9

81.5

81.0

81.1

18

79.5

80.6

81.3

80.8

79.7

9

79.5

78.8

79.4

79.0

81.0

19

80.7

81.0

79.5

80.0

79.0

10

80.3

81.2

79.7

78.9

80.3

20

78.8

79.6

79.6

80.6

80.7

<Problem3-B>

Data-entryclerksatARCOkeyinthousandsofinsurancerecordseachday.Samplesoftheworkof20clerksareshowninthetable.Onehundredrecordsenteredbyeachclerkwerecarefullyexaminedandthenumberoferrorscounted.Thefractiondefectiveineachsamplewasthencomputed.

Setthecontrollimitstoinclude99.73%oftherandomvariationintheentryprocesswhenitisincontrol.

SampleNumber

NumberofErrors

FractionDefective

SampleNumber

NumberofErrors

FractionDefective

1

2

3

4

5

6

7

8

9

10

6

5

0

1

4

2

5

3

3

2

.06

.05

.00

.01

.04

.02

.05

.03

.03

.02

11

12

13

14

15

16

17

18

19

20

6

1

8

7

5

4

11

3

0

4

.06

.01

.08

.07

.05

.04

.11

.03

.00

.04

<Questions>

Hastheprocessbeenincontrol?

Supposeweusea95percentp-chart.Whataretheupperandlowercontrollimits?Hastheprocessgottenmoreoutofcontrol?

Supposethatthesamplesizeusedwasactually120insteadofthe100thatitwassupposedtobe.Howdoesthisaffectthechart?

Whathappenstothechartaswereducethez-value?

Whathappenstothechartaswereducethepercentage?

<Problem3-C>

InaGEinsuranceclaimsprocess,minutes,andminutes.

Thedesignspecificationtomeetcustomerexpectationsis210±3minutes.SotheUpperSpecificationis213minutesandthelowerspecificationis207minutes.

Sincearatioof1.00meansthat99.73%ofaprocess’soutputsarewithinspecifications,thisratiosuggestsaverycapableprocess,withnonconformanceoflessthan4claimspermillion.

<Questions>

Howfarcanthemeanshifttotherightbeforethecurveextendsovertheupperspecification?HowdoesthisaffecttheCpandCpk?

Increasethestandarddeviation.Atwhatvaluewillthecurvecrosstheupperspecification?

<Problem3-D>

AProcessfillingsmallbottleswithbabyformulahasatargetof3±0.15ounces.Two-hundredbottlesfromtheprocessweresampled.Theresultsshowedtheaverageamountofformulaplacedinthebottleswas3.042ounces.Thestandarddeviationoftheamountswas0.034ounces.

<Questions>

DeterminethevalueofCpk.

Roughlywhatproportionofbottlesmeetsthespecifications?

Problem#4-AcceptalbeSamplingandOCCurve

Ashipmentof2,000portablebatteryunitsformicrocomputersisabouttobeinspectedbyaMalaysianimporter.TheKoreanmanufacturerandtheimporterhavesetupasamplingplaninwhichtheαriskislimitedto5%atanacceptablequalitylevel(AQL)of2%defective,andtheβriskissetto10%atLotTolerancePercentDefective(LTPD)=7%defective.WewanttoconstructtheOCcurvefortheplanofn=120samplesizeandanacceptancelevelofc≤3defectives.

Tosolvetheproblem,weturntothecumulativePoissontable,whosecolumnsaresetupintermsoftheacceptancelevel,c.Weareinterestedonlyinthec=3columnforthisexample.Therowsinthetableareλ(=np),whichrepresentsthenumberofdefectswewouldexpectt