2007 Mathematics. Standard Grade Credit. Finalised Marking Instructions

Transcription

1 007 Mathematics Standard Grade Credit Finalised Marking Instructions Scottish Qualifications Authority 007 The information in this publication may be reproduced to support SQA qualifications only on a non-commercial basis. If it is to be used for any other purposes written permission must be obtained from the Assessment Materials Team, Dalkeith. Where the publication includes materials from sources other than SQA (secondary copyright), this material should only be reproduced for the purposes of examination or assessment. If it needs to be reproduced for any other purpose it is the centre's responsibility to obtain the necessary copyright clearance. SQA's Assessment Materials Team at Dalkeith may be able to direct you to the secondary sources. These Marking Instructions have been prepared by Examination Teams for use by SQA Appointed Markers when marking External Course Assessments. This publication must not be reproduced for commercial or trade purposes.

2 Special Instructions The main principle in marking scripts is to give credit for the skills which have been demonstrated. Failure to have the correct method may not preclude a pupil gaining credit for the calculations involved or for the communication of the answer. Care should be taken to ensure that the mark for any question or part question is entered in the correct column, as indicated by the horizontal line. Where a candidate has scored zero marks for any question attempted, "0" should be shown against the answer in the appropriate column. It is of great importance that the utmost care should be exercised in adding up the marks. Where appropriate, all summations for totals and grand totals must be carefully checked. The answer to one part, correct or incorrect must be accepted as a basis for subsequent dependent parts of a question. Full marks in the dependent part is possible if it is of equivalent difficulty. 3 Do not penalise insignificant errors. An insignificant error is one which is significantly below the level of attainment being assessed. eg An error in the calculation of would not be penalised at Credit Level. 4 Working after a correct answer should only be taken into account if it provides firm evidence that the requirements of the question have not been met. 5 In certain cases an error will ease subsequent working. Full credit cannot be given for this subsequent work but partial credit may be given. 6 Accept answers arrived at by inspection or mentally, where it is possible for the answer to have been so obtained. 7 Do not penalise omission or misuse of units unless marks have been specifically allocated to units. Page

3 8 A wrong answer without working receives no credit unless specifically mentioned in the marking scheme. The rubric on the outside of the Papers emphasises that working must be shown. In general markers will only be able to give credit to partial answers if working is shown. However there may be a few questions where partially correct answers unsupported by working can still be given some credit. Any such instances will be stated in the marking scheme. 9 Acceptable alternative methods of solution can only be given the marks specified, ie a more sophisticated method cannot be given more marks. te that for some questions a method will be specified. 0 In general do not penalise the same error twice in the one question. Accept legitimate variations in numerical/algebraic questions. Do not penalise bad form eg sinx 0 = 0 5 = A transcription error is not normally penalised except where the question has been simplified as a result. Page 3

4 007 Mathematics SG Credit Level Paper Marking Instructions Award marks in whole numbers only Question Ans: knowing correct order of operations carrying out both calculations KU (i) for with or without working award (ii) for 74 4 with or without working award (iii) for 95 with or without working award (iv) for 3 48 with or without working award (v) for any other answer without working award 0 Page 4

5 Ans: 9 0 expressing as a multiplication 3 5 carrying out the multiplication 9 or equivalent 0 KU 9 (i) for with or without working award 0 95 (ii) for with or without working award 8 (iii) for any other answer without working award 0 (iv) for the second mark, the only acceptable multipliers are 5 3 or 3 5 Page 5

6 3 Ans: 50 valid strategy multiplication by 8 5 solution 50 RE (i) for an answer of 50 without working award (ii) for an answer of with working award (iii) for an answer of 000 with or without working award 0 Page 6

7 4 Ans: = P 3 m or m = P + 4 Method : dealing with denominator dealing with constant dealing with coefficient 3P 3 P + 8 = m 3 P + 8 Method : dealing with denominator 3P dealing with coefficient dealing with constant 3P = m 4 3 P + 4 3KU Page 7

8 5 Ans: x + x + 7 expanding first bracket expanding second bracket collecting terms 4x + 6x + 6x + 9 3x + 8 x + x + 7 3KU (i) the third mark is available only when an x term is involved Page 8

9 4 6 Ans: f = d + 5 gradient y-intercept linear equation equation in terms of d and f y = x f = d + 5 4KU (i) for a correct equation without working award 4 4 (ii) where the gradient and/or y-intercept are wrong, but explicitly stated, the 3 rd and 4 th marks are still available (iii) for an answer of 4 f = d award 5 4 (unless the y-intercept has been explicitly stated as zero, in which case, award 4 3 ) (iv) for an answer of 4 f = d + c 5 award 4 (v) an equation involving transposition of f and d may be awarded a maximum of 4 3 Page 9

10 7 Ans: a a starting to expand bracket completing expansion a or a a a KU (i) accept a (ii) ignore any working subsequent to a correct answer Page 0

11 8 Ans: yes, plus valid reason valid scale factor or applying scale factor or calculation and reason yes, as 90 cm is greater than required length of 80 cm 3RE (i) reason must contain a numerical comparison within a valid strategy Page

12 9 Ans: 3 forming equation solution x + x x = 8 = 6 simplification 3 3RE (i) the third mark is obtained only for the simplification of a surd Page

13 0 Ans: multiplied by 8 (or divided by 8) effect on 3 L k effect on 3 L ( L ) 3 or 8 8 RE (i) finding values for T and T using a numerical value for L may be awarded the st mark (ii) an explicit statement is necessary for the nd mark Page 3

14 (a) Ans: x + y = 300 equation x + y = 300 KU (b) Ans: 4 x + 6 y = 380 terms equation 4x and 6y 4 x + 6y = 380 KU (c) Ans: 0 standard and 90 deluxe evidence of scaling value of x value of y 4 x + 4y = 00 or equivalent RE (i) for 90 and 0 without working award 3 0 (ii) for 90 and 0 verified in both equations award 3 Page 4

15 Ans: cm valid strategy method process recognition of right angle at chord correct use of Pythagoras 3 solution d = 4RE (i) for using a radius of 0 to obtain d = 0 84, award a maximum of 3 marks ( st, 3 rd and 4 th ) Page 5

16 3 Ans: b =, c = 3 value of b value of c 3 KU (i) for, 3 award (ii) for (b =) 3, (c = ) award 0 Page 6

17 4 (a) Ans: 8 solution 8 RE (b) Ans: 4 substitution solution n 3 = 80 4 RE (i) for evidence of implicit substitution (eg 8) award the st mark (ii) for an answer of 4 with or without working award KU marks RE 0 marks [END OF PAPER MARKING INSTRUCTIONS] Page 7