.
Comparison of key skills specifications 2000/2002 with 2004 standardsX015461July 2004Issue 1
GCE A level Statistics (9MA0) – Paper 31
Statistics
October 2021 student-friendly mark scheme
Please note that this mark scheme is not the one used by examiners for
making scripts. It is intended more as a guide to good practice, indicating
where marks are given for correct answers. As such, it doesn’t show
follow-through marks (marks that are awarded despite errors being made) or
special cases.
It should also be noted that for many questions, there may be alternative
methods of finding correct solutions that are not shown here – they will be
covered in the formal mark scheme.
This document is intended for guidance only and may differ significantly from
the final mark scheme published in December 2021.
Guidance on the use of codes within this document
M1 – method mark. This mark is generally given for an appropriate method in
the context of the question. This mark is given for showing your working and
may be awarded even if working is incorrect.
A1 – accuracy mark. This mark is generally given for a correct answer
following correct working.
B1 – accuracy mark. This mark is usually given when working and the answer
cannot easily be separated.
Some questions require all working to be shown; in such questions, no marks
will be given for an answer with no working (even if it is a correct answer).
This study source was downloaded by 100000842568006 from CourseHero.com on 05-13-2022 16:27:35 GMT -05:00
https://www.coursehero.com/file/122395872/AL-Statistics-October-2021-mark-scheme-student-friendlydocxpdf/
, Question 1 (Total 7 marks)
Part Working or answer an examiner might expect Mark Notes
to see
(a) Disadvantage: e.g. Not random; cannot use B1 This mark is given for a suitable
(reliably) for inferences disadvantage.
(b) X ~B(36, 0.08) M1 This mark is given for stating
B(36,0.08) or in words.
(i) P(X = 4) = 0.167387… A1 This mark is given for the correct
= 0.167 value.
(ii) A1 This mark is given for the correct
0.022233… value.
= 0.0222
(c) P(In dance club and dance tango) = B1 This mark is given for the correct
probability.
= 0.032
(d) Let T = those who can dance the Tango. M1 This mark is given for stating
T ~B(50, 0.032) B(50,0.032)
A1 This mark is given for the correct
P(T < 3 ) = P(T 2) = 0.7850815… value.
= 0.785
Question 2 (Total 6 marks)
Part Working or answer an examiner might expect Mark Notes
to see
(a) Negative B1 This mark is given for negative
correlation.
(b) Marc’s suggestion is compatible because it’s B1 This mark is given for suitable
negative correlation comment to suggest data is compatible
and suitable reason such as negative
correlation.
(c) r = – 0.54458266… B1 This mark is given for the correct value
= – 0.545 of r.
(d) B1 This mark is given for both hypotheses
correct in terms of .
5% 1-tail critical value = – 0.4259 M1 This mark is given for finding the
critical value.
significant result / reject H0 A1 This mark is given for correct
There is evidence of negative correlation conclusion in context.
between the number of letters in a student’s
last name and their first name
GCE A level Pure Mathematics (9MA0) – Paper 31 Statistics model solutions (Version 1.0)
2
This document is intended for guidance only and may differ significantly from the final mark scheme published in December 2021.
This study source was downloaded by 100000842568006 from CourseHero.com on 05-13-2022 16:27:35 GMT -05:00
https://www.coursehero.com/file/122395872/AL-Statistics-October-2021-mark-scheme-student-friendlydocxpdf/
Comparison of key skills specifications 2000/2002 with 2004 standardsX015461July 2004Issue 1
GCE A level Statistics (9MA0) – Paper 31
Statistics
October 2021 student-friendly mark scheme
Please note that this mark scheme is not the one used by examiners for
making scripts. It is intended more as a guide to good practice, indicating
where marks are given for correct answers. As such, it doesn’t show
follow-through marks (marks that are awarded despite errors being made) or
special cases.
It should also be noted that for many questions, there may be alternative
methods of finding correct solutions that are not shown here – they will be
covered in the formal mark scheme.
This document is intended for guidance only and may differ significantly from
the final mark scheme published in December 2021.
Guidance on the use of codes within this document
M1 – method mark. This mark is generally given for an appropriate method in
the context of the question. This mark is given for showing your working and
may be awarded even if working is incorrect.
A1 – accuracy mark. This mark is generally given for a correct answer
following correct working.
B1 – accuracy mark. This mark is usually given when working and the answer
cannot easily be separated.
Some questions require all working to be shown; in such questions, no marks
will be given for an answer with no working (even if it is a correct answer).
This study source was downloaded by 100000842568006 from CourseHero.com on 05-13-2022 16:27:35 GMT -05:00
https://www.coursehero.com/file/122395872/AL-Statistics-October-2021-mark-scheme-student-friendlydocxpdf/
, Question 1 (Total 7 marks)
Part Working or answer an examiner might expect Mark Notes
to see
(a) Disadvantage: e.g. Not random; cannot use B1 This mark is given for a suitable
(reliably) for inferences disadvantage.
(b) X ~B(36, 0.08) M1 This mark is given for stating
B(36,0.08) or in words.
(i) P(X = 4) = 0.167387… A1 This mark is given for the correct
= 0.167 value.
(ii) A1 This mark is given for the correct
0.022233… value.
= 0.0222
(c) P(In dance club and dance tango) = B1 This mark is given for the correct
probability.
= 0.032
(d) Let T = those who can dance the Tango. M1 This mark is given for stating
T ~B(50, 0.032) B(50,0.032)
A1 This mark is given for the correct
P(T < 3 ) = P(T 2) = 0.7850815… value.
= 0.785
Question 2 (Total 6 marks)
Part Working or answer an examiner might expect Mark Notes
to see
(a) Negative B1 This mark is given for negative
correlation.
(b) Marc’s suggestion is compatible because it’s B1 This mark is given for suitable
negative correlation comment to suggest data is compatible
and suitable reason such as negative
correlation.
(c) r = – 0.54458266… B1 This mark is given for the correct value
= – 0.545 of r.
(d) B1 This mark is given for both hypotheses
correct in terms of .
5% 1-tail critical value = – 0.4259 M1 This mark is given for finding the
critical value.
significant result / reject H0 A1 This mark is given for correct
There is evidence of negative correlation conclusion in context.
between the number of letters in a student’s
last name and their first name
GCE A level Pure Mathematics (9MA0) – Paper 31 Statistics model solutions (Version 1.0)
2
This document is intended for guidance only and may differ significantly from the final mark scheme published in December 2021.
This study source was downloaded by 100000842568006 from CourseHero.com on 05-13-2022 16:27:35 GMT -05:00
https://www.coursehero.com/file/122395872/AL-Statistics-October-2021-mark-scheme-student-friendlydocxpdf/
