University of Cape TownCOMPUTER S AQAAQA-75171-W-MS-JUN18

Paper 1 (7517/1) – applicable to all programming languages A, B, C, D and E June 2018 The following annotation is used in the mark scheme: ; - means a single mark // - means an alternative response / - means an alternative word or sub-phrase A - means an acceptable creditworthy answer R - means reject answer as not creditworthy NE - means not enough I - means ignore DPT - means "Don't penalise twice". In some questions a specific error made by a candidate, if repeated, could result in the loss of more than one mark. The DPT label indicates that this mistake should only result in a candidate losing one mark, on the first occasion that the error is made. Provided that the answer remains understandable, subsequent marks should be awarded as if the error was not being repeated. Pages 4 to 5 contain ‘Level of Response’ marking instructions. Pages 6 to 21 contain the generic mark scheme. Pages 21 to 43 contain the ‘Program Source Code’ specific to the programming languages for questions 5, 7, 8, 9, 10 and 11. pages 21 to 23 – PYTHON 2 pages 24 to 26 – PYTHON 3 pages 26 to 30 – VB.NET pages 31 to 35 – C# pages 36 to 40 – JAVA pages 41 to 43 – PASCAL/Delphi MARK SCHEME – A-LEVEL COMPUTER SCIENCE – 7517/1 – JUNE 2018 4 Level of response marking instructions Level of response mark schemes are broken down into levels, each of which has a descriptor. The descriptor for the level shows the average performance for the level. There are marks in each level. Before you apply the mark scheme to a student’s answer read through the answer and annotate it (as instructed) to show the qualities that are being looked for. You can then apply the mark scheme. Step 1 Determine a level Start at the lowest level of the mark scheme and use it as a ladder to see whether the answer meets the descriptor for that level. The descriptor for the level indicates the different qualities that might be seen in the student’s answer for that level. If it meets the lowest level then go to the next one and decide if it meets this level, and so on, until you have a match between the level descriptor and the answer. With practice and familiarity you will find that for better answers you will be able to quickly skip through the lower levels of the mark scheme. When assigning a level you should look at the overall quality of the answer and not look to pick holes in small and specific parts of the answer where the student has not performed quite as well as the rest. If the answer covers different aspects of different levels of the mark scheme you should use a best fit approach for defining the level and then use the variability of the response to help decide the mark within the level, ie if the response is predominantly level 3 with a small amount of level 4 material it would be placed in level 3 but be awarded a mark near the top of the level because of the level 4 content. Step 2 Determine a mark Once you have assigned a level you need to decide on the mark. The descriptors on how to allocate marks can help with this. The exemplar materials used during standardisation will help. There will be an answer in the standardising materials which will correspond with each level of the mark scheme. This answer will have been awarded a mark by the Lead Examiner. You can compare the student’s answer with the example to determine if it is the same standard, better or worse than the example. You can then use this to allocate a mark for the answer based on the Lead Examiner’s mark on the example. You may well need to read back through the answer as you apply the mark scheme to clarify points and assure yourself that the level and the mark are appropriate. Indicative content in the mark scheme is provided as a guide for examiners. It is not intended to be exhaustive and you must credit other valid points. Students do not have to cover all of the points mentioned in the Indicative content to reach the highest level of the mark scheme. An answer which contains nothing of relevance to the question must be awarded no marks.