Please check the examination details below before entering your candidate information
Candidate surname Other names
Centre Number Candidate Number
Pearson Edexcel Level 3 GCE
Time 2 hours
Paper
reference 9ST0/02
Statistics
Advanced
PAPER 2: Statistical Inference
You must have: Total Marks
Statistical formulae and tables
booklet Calculator
A-Level Pearson Edexcel Level 3GCE
In Statistics (9ST0/02)
Paper 02: Statistical Inference Summer
Exam Paper
(AUTHENTIC MAKING SCHEME)
Q:1/1/1/
*P69433A0120*
P69433A
©2022 Pearson Education Ltd.
, Answer ALL questions. Write your answers in the spaces provided.
1 The breaking strength of cables has usually been assessed by testing samples of cables
until they break (testing to destruction).
A manufacturer of carbon-fibre-reinforced polymer (CFRP) cables wants to replace
testing to destruction with a method for predicting breaking strength based on known
characteristics of a cable.
The methods to be compared are a computer simulation model and a
mathematical model.
The investigation involves selecting a sample of 18 CFRP cables. Nine of them have
their breaking strengths predicted by a computer simulation model and nine by a
mathematical model.
Each cable is then tested to destruction to determine its actual breaking strength.
The following are the percentage errors made in the predictions for each model.
A negative error means that the prediction is too low.
Previous research suggests that percentage errors such as these have skew distributions.
Computer model Mathematical model
–7.5 4.4
–3.2 8.3
–3.3 8.2
–5 6.9
–1.5 10.1
–0.6 10.9
0.7 12.2
4.8 15.9
5.2 15.9
[Data source: https://doi.org/10.1590/1679-78254177]
2
*P69433A0220*
,Question 1 continued
(a) Perform a non-parametric test to decide whether there is evidence of a difference in
the average prediction error of these models.
(9)
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3
*P69433A0320* Turn over
, Question 1 continued
Khalid, a junior researcher, instead suggested evaluating the methods by comparing
mean percentage error using a t-test.
(b) Make two comments on the suitability of this suggestion.
(2)
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
Lauren, the chief engineer, suggests that, to make the comparison, it would have been
better to run both the computer and mathematical models using the same cables, and
then testing each to destruction.
(c) State, with justification, whether or not you agree with Lauren’s suggestion.
(2)
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
(d) Suggest a test that Lauren could use to compare the two methods.
(2)
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
(Total for Question 1 is 15 marks)
4
*P69433A0420*
Candidate surname Other names
Centre Number Candidate Number
Pearson Edexcel Level 3 GCE
Time 2 hours
Paper
reference 9ST0/02
Statistics
Advanced
PAPER 2: Statistical Inference
You must have: Total Marks
Statistical formulae and tables
booklet Calculator
A-Level Pearson Edexcel Level 3GCE
In Statistics (9ST0/02)
Paper 02: Statistical Inference Summer
Exam Paper
(AUTHENTIC MAKING SCHEME)
Q:1/1/1/
*P69433A0120*
P69433A
©2022 Pearson Education Ltd.
, Answer ALL questions. Write your answers in the spaces provided.
1 The breaking strength of cables has usually been assessed by testing samples of cables
until they break (testing to destruction).
A manufacturer of carbon-fibre-reinforced polymer (CFRP) cables wants to replace
testing to destruction with a method for predicting breaking strength based on known
characteristics of a cable.
The methods to be compared are a computer simulation model and a
mathematical model.
The investigation involves selecting a sample of 18 CFRP cables. Nine of them have
their breaking strengths predicted by a computer simulation model and nine by a
mathematical model.
Each cable is then tested to destruction to determine its actual breaking strength.
The following are the percentage errors made in the predictions for each model.
A negative error means that the prediction is too low.
Previous research suggests that percentage errors such as these have skew distributions.
Computer model Mathematical model
–7.5 4.4
–3.2 8.3
–3.3 8.2
–5 6.9
–1.5 10.1
–0.6 10.9
0.7 12.2
4.8 15.9
5.2 15.9
[Data source: https://doi.org/10.1590/1679-78254177]
2
*P69433A0220*
,Question 1 continued
(a) Perform a non-parametric test to decide whether there is evidence of a difference in
the average prediction error of these models.
(9)
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
3
*P69433A0320* Turn over
, Question 1 continued
Khalid, a junior researcher, instead suggested evaluating the methods by comparing
mean percentage error using a t-test.
(b) Make two comments on the suitability of this suggestion.
(2)
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
Lauren, the chief engineer, suggests that, to make the comparison, it would have been
better to run both the computer and mathematical models using the same cables, and
then testing each to destruction.
(c) State, with justification, whether or not you agree with Lauren’s suggestion.
(2)
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
(d) Suggest a test that Lauren could use to compare the two methods.
(2)
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
(Total for Question 1 is 15 marks)
4
*P69433A0420*
