Mark Scheme (Results)
Summer 2023
Pearson Edexcel GCE
In Statistics (9ST0)
Paper 02: Statistical InferenceEdexcel and BTEC Qualifications
Edexcel and BTEC qualifications are awarded by Pearson, the UK’s largest awar
...
Mark Scheme (Results)
Summer 2023
Pearson Edexcel GCE
In Statistics (9ST0)
Paper 02: Statistical InferenceEdexcel and BTEC Qualifications
Edexcel and BTEC qualifications are awarded by Pearson, the UK’s largest awarding body. We
provide a wide range of qualifications including academic, vocational, occupational and specific
programmes for employers. For further information visit our qualifications websites at
www.edexcel.com or www.btec.co.uk. Alternatively, you can get in touch with us using the
details on our contact us page at www.edexcel.com/contactus.
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Summer 2023
Publications Code 9ST0_02_2306_MS
All the material in this publication is copyright
© Pearson Education Ltd 2023General Marking Guidance
• All candidates must receive the same
treatment. Examiners must mark the first candidate in
exactly the same way as they mark the last.
• Mark schemes should be applied positively. Candidates
must be rewarded for what they have shown they can do
rather than penalised for omissions.
• Examiners should mark according to the mark scheme
not according to their perception of where the grade
boundaries may lie.
• There is no ceiling on achievement. All marks on the mark
scheme should be used appropriately.
• All the marks on the mark scheme are designed to be
awarded. Examiners should always award full marks if
deserved, i.e. if the answer matches the mark
scheme. Examiners should also be prepared to award
zero marks if the candidate’s response is not worthy of
credit according to the mark scheme.
• Where some judgement is required, mark schemes will
provide the principles by which marks will be awarded
and exemplification may be limited.
• When examiners are in doubt regarding the application
of the mark scheme to a candidate’s response, the team
leader must be consulted.
• Crossed out work should be marked UNLESS the
candidate has replaced it with an alternative response.General Marking Guidance
Total marks
The total number of marks for the paper is 80.
Mark types
The Edexcel Statistics mark schemes use the following types of marks:
• M Method marks,
awarded for ‘knowing a method and attempting to apply it’,
unless otherwise indicated.
• A Accuracy marks can only be awarded if the relevant method (M)
marks
have been earned.
• B Unconditional accuracy marks are independent of M marks
• E Explanation marks
NOTE: Marks should not be subdivided.
Abbreviations
These are some of the marking abbreviations that will appear in the mark
schemes.
• ft follow through
• PI possibly implied
• cao correct answer only
• cso correct solution only
(There must be no errors in this part of the question)
• awrt answers which round to
• awfw answers which fall within (a given range)
• SC special case
• nms no method shown
• oe or equivalent
• dep dependent (on a given mark or objective)
• dp decimal places
• sf significant figures
• The answer is printed on the paperFurther notes
• All candidates must receive the same treatment. Examiners must mark the
first candidate in exactly the same way as they mark the last.
• Mark schemes should be applied positively. Candidates must be rewarded
for what they have shown they can do rather than penalised for omissions.
• Examiners should mark according to the mark scheme not according to
their perception of where the grade boundaries may lie.
• There is no ceiling on achievement. All marks on the mark scheme should
be used appropriately.
• All the marks on the mark scheme are designed to be awarded. Examiners
should always award full marks if deserved, i.e. if the answer matches the
mark scheme. Examiners should also be prepared to award zero marks if
the candidate’s response is not worthy of credit according to the mark
scheme.
• Where some judgement is required, mark schemes will provide the
principles by which marks will be awarded and exemplification may be
limited.
• When examiners are in doubt regarding the application of the mark scheme
to a candidate’s response, the team leader must be consulted.
• All A marks are ‘correct answer only’ (cao), unless shown, for example, as
A1ft to indicate that previous wrong working is to be followed through.
• All M marks are ‘possibly implied’ (PI) unless specifically stated otherwise in
the ‘Notes’ column.
• After a misread, the subsequent A marks affected are treated as A1ft, but
manifestly absurd answers should never be awarded A marks.
• Crossed out work should be marked UNLESS the candidate has replaced it
with an alternative response.
• If two solutions are given, each should be marked, and the resultant mark
should be the mean of the two marks, rounded down to the nearest integer
if needed.Question Scheme Marks AO Notes
1(a) Wilcoxon Rank Sum M1 2.1a
Used or clearly stated
or
Mann-Whitney (U
test) stated
H0: 𝜂𝐴 = 𝜂𝐵
H1: 𝜂𝐴 > 𝜂𝐵
B1 1.3
H0: Samples from
identical populations
H1: Samples from
different populations
oe
Asia (A) Not Asia (B)
1 20
2 19
3 18
5 16
7 14
9 12
16 5
17 4
4 17
6 15
8 13
10 11
11 10
12 9
13 8
14 7
15 6
18 3
19 2
20 1
M1 1.3 Attempt at ranking as
one group
A1 1.3
All ranking correct
Or reversed ranks
TA=60 or TB=150 M1dep 1.3
Effort to obtain T
(reverse totals
108,102)
𝑈𝐴 = 60 −
1 2
(8)(9) = 24
𝑈𝐵 = 150 −
1 2
(12)(13) = 72
A1 1.3 Either U correctQuestion Scheme Marks AO Notes
cv=26 (or 70) B1 1.3 Either cv correct
“24” < “26” (or 72>70)
Reject H0
M1 2.1b Correct conclusion for
their ts and their cv
There is significant evidence at the
5% level that players from Asian
countries do better than those from
non-Asian countries
E1dep 2.1a Dep on correct ts & cv
1(b) Possible improvements (not
exhaustive)
Use a larger sample size Larger than 30 so
CLT can be used
Ensure sample is randomly selected
Select sample from all professional
players not just those taking part in
the world cup
Use more than one video game
Use equal sample sizes
Use sample from more than one
event
E1 3.1a Any sensible
suggestion
1(c) Numbers of points may not be
normally distributed.
Positions are discrete rather than
continuous.
It is not known whether the
variances are equal.
E1 3.1a Any of theseQuestion Scheme Marks AO
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