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Pearson Edexcel Level 3 GCE l l l l
Paper
Mathematics
reference 9MA0/31
Advanced
PAPER 31: Statistics
l l
Youlmustlhave: TotallMarks
MathematicallFormulaelandlStatisticallTablesl(Green),lcalculator
A-
LEVEL PEARSON EDEXEL 9MAO/31 A-
l l l l
LEVEL 3 GCE MATHEMATICS ADVANC
l l l l
ED PAPER 31 STATISTICS l l l l
l (AUTHENTIC MARKING SCHEME ATT l l l
ACHED)
Q:1/1/1/1/
*P72130A0120*
©2022lPearsonlEducationlLtd.
,1. Georgelthrowslalballlatlaltargetl15ltimes.
EachltimelGeorgelthrowslthelball,lthelprobabilityloflthelballlhittingltheltargetlisl0.48
ThelrandomlvariablelXlrepresentslthelnumberlofltimeslGeorgelhitsltheltargetlinl15lth
rows.
(a) Find
(i) P (Xl=l3)
(ii) P (Xlll5)
(3)
Georgelnowlthrowslthelballlatltheltargetl250ltimes.
(b) Uselalnormallapproximationltolcalculatelthelprobabilitylthatlhelwilllhitltheltargetlmor
elthanl110ltimes.
(3)
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2
*P72130A0220*
,Questionl1lcontinued
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(TotallforlQuestionl1lisl6lmarks)
3
*P72130A0320* Turnloverl
, 2. Almanufacturerluseslalmachineltolmakelmetallrods.
Thellengthloflalmetallrod,lL cm,lislnormallyldistributedlwith
• almeanlofl8 cm
• alstandardldeviationloflx cm
Givenlthatlthelproportionloflmetallrodsllesslthanl7.902 cmlinllengthlisl2.5%l(a)ls
howlthatlxl=l0.05ltol2ldecimallplaces.
(2)
(b) Calculatelthelproportionloflmetallrodslthatlarelbetweenl7.94 cmlandl8.09 cmlinll
ength.
(1)
Thelcostloflproducinglalsinglelmetallrodlisl20p
Almetallrod
• wherelLl<l7.94lislsoldlforlscraplforl5p
• wherel7.94lllLlll8.09lislsoldlforl50p
• wherelLl>l8.09lislshortenedlforlanlextralcostlofl10plandlthenlsoldlforl50p
(c) Calculatelthelexpectedlprofitlperl500loflthelmetallrods.lGi
velyourlanswerltolthelnearestlpound.
(5)
Thelsamelmanufacturerlmakeslmetallhingeslinllargelbatches.
Thelhingesleachlhavelalprobabilitylofl0.015loflhavinglalfault.
Alrandomlsamplelofl200lhingeslisltakenlfromleachlbatchlandlthelbatchlislacceptedliflfewerl
thanl6lhingeslarelfaulty.
Thelmanufacturer'slaimlislforl95%loflbatchesltolbelaccepted.
(d)lExplainlwhetherlthelmanufacturerlisllikelyltolachievelitslaim.
(4)
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*P72130A0420*