Cambridge A Level Information Technology (from 2017) 9626 — 2019 May/June Paper 1 · Variant 2

This document consists of 18 printed pages and 2 blank pages. DC (SC/TP) 163072/3 © UCLES 2019 [Turn over Cambridge Assessment International Education Cambridge International Advanced Subsidiary and Advanced Level * 0 7 7 1 1 0 4 8 6 5 * INFORMATION TECHNOLOGY 9626/12 Paper 1 Theory May/June 2019 1 hour 45 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your centre number, candidate number and name in the spaces at the top of this page. Write in dark blue or black pen. You may use an HB pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. Calculators must not be used on this paper. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. Any businesses described in this paper are entirely fictitious.

2 9626/12/M/J/19 © UCLES 2019 1 Tick the four statements referring to asymmetric encryption which are true. ✓ It is often referred to as public key encryption It uses a pair of keys, a public key and a private key The public key and the private key are published to everyone who wants to send a message Anyone with a copy of the public key can read encrypted data It is possible to deduce the private key from the public key SSL is a protocol that uses asymmetric encryption Keys used in symmetric encryption are longer, compared to asymmetric keys Asymmetric encryption is slower to convert than symmetric encryption and requires far more processing power Digital certificates are not used with asymmetric encryption The use of an asymmetric key algorithm always ensures security of a message [4] 2 Tick the four statements referring to malware which are true. ✓ A virus corrupts files but does not delete them Ransomware continually deletes files until a ransom is paid One purpose of releasing a worm is to occupy as much bandwidth in a network as possible Ransomware is often initiated by means of a trojan horse A trojan horse is a type of malware within an email attachment that is downloaded without the user understanding the consequences Spyware is a type of software that removes key loggers from a hard disk Adware is additional software attached to a virus when it is downloaded Malicious bots are never used to instigate a SPAM attack A rootkit enables a hacker to gain administrator rights in a victim’s computer A trojan horse just enables a virus to be transmitted. It never deletes data itself [4]

3 9626/12/M/J/19 © UCLES 2019 [Turn over 3 People in a village are aware that the local river is being polluted. They are concerned that this is being caused by a nearby factory. Describe how computers and sensors could be used to monitor the level of pollution in the river in order to determine whether the factory is responsible for the pollution. … … … … … … … … … … … …[5]

4 9626/12/M/J/19 © UCLES 2019 4 Some people get confused when trying to establish what is data, information or knowledge. The sequence of numbers 192.168.1.254 could be an example of data. Using this example, or another of your choice, explain how data, information and knowledge are linked. … … … … … … … … … …[4]

5 9626/12/M/J/19 © UCLES 2019 [Turn over 5 A large company with branches in many countries has decided to install a Virtual Private Network (VPN). (a) Describe the purpose of such a network. … … … … … …[2] (b) Explain how it achieves this purpose. … … … … … … … … … …[4]

6 9626/12/M/J/19 © UCLES 2019 6 Video‑conferencing is a commonly used method of communication. It has affected different sections of society. Describe two effects of video‑conferencing for each of the following groups of people: Legislators (government members who make legislation or laws) 1 … … … 2 … … … Business people 1 … … … 2 … … … Television news presenters 1 … … … 2 … … … [6]

7 9626/12/M/J/19 © UCLES 2019 [Turn over 7 Relational databases can have many components and properties. (a) Describe what is meant by the following terms: (i) Primary key … … … (ii) Foreign key … … … (iii) Compound key … … …[3] (b) Explain why referential integrity is important in a relational database. … … … … … … … …[3]

8 9626/12/M/J/19 © UCLES 2019 8 The owners of a bank are considering changing its system of reading cheques from Magnetic Ink Character Recognition (MICR) to Optical Character Recognition (OCR). Give two advantages and two disadvantages of using OCR instead of MICR. Advantage 1 … … … Advantage 2 … … … Disadvantage 1 … … … Disadvantage 2 … … …[4]

9 9626/12/M/J/19 © UCLES 2019 [Turn over 9 An expert system consists of many components. Describe how the knowledge base is used to interact with the other components when an expert system is used to solve a problem. … … … … … … … … … … … …[5]

10 9626/12/M/J/19 © UCLES 2019 10 An examinations officer has created a spreadsheet containing a list of students and their dates of birth. It will be used to calculate each student’s age in years. This is the age that they will be on the date of a science exam which is on 21/05/2019. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Family name Age First name Date of birth (dd/mm/yyyy) Purewal Jones Astle Herreira Maninga Charlton van Gaal Alonso Lagat Kibaki Mbabasi Dansua Kirshwan Patel Bhutto Abbasi Kunwar al-Hafi Hala Namet Sandeep Ieuan Roberta David Jeff Leona Ruud Maria Mary Robert Apolo Albert Kiran Alpa Waseem Akhtar Ishwar Saad Bassem Fawzi 17/05/2002 15/10/2001 21/07/2002 10/08/2002 17/09/2001 08/03/2002 09/02/2002 17/11/2001 10/11/2001 13/04/2002 30/06/2002 24/06/2002 30/08/2002 15/03/2002 14/09/2001 18/12/2001 16/01/2002 14/03/2001 25/05/2002 31/05/2002 17 17 16 16 17 17 17 17 17 17 16 16 16 17 17 17 17 18 16 16 4 3 4 4 3 4 4 3 3 4 5 4 3 4 3 4 3 4 5 4 6 4 A B C D E F G H 21/05/2019 number of students aged 17 taking 3 exams number of students aged 16 taking 4 exams Number of exams entered for (a) She entered a formula in D4 to calculate the student’s age. Write down the formula she used. This formula should be easy to replicate. You can assume for the purpose of this exercise that the number of days in a year averages out to 365.25. = …[4] You can use the space below for any working you need.

11 9626/12/M/J/19 © UCLES 2019 [Turn over (b) (i) The spreadsheet is to be sorted in ascending order of Age and then descending order of Number of exams entered for. Write down the values which would be displayed in D9 and E9. …[2] You can use the space below for any working you need. (ii) The original spreadsheet is to be sorted in descending order of Age and then ascending order of Number of exams entered for. Write down the values which would be displayed in D17 and E17. …[2] You can use the space below for any working you need. (c) A teacher wanted to know the number of students aged 17 taking three exams. Write down the formula containing a counting function she used in cell G4 to calculate this number. This formula should work even if the data changes. = …[5] You can use the space below for any working you need.

12 9626/12/M/J/19 © UCLES 2019 (d) The teacher now wants to know the number of students aged 16 taking four exams. Write down the formula containing a counting function she used in cell G5 to calculate this number. This formula should work even if the data changes. …[3] You can use the space below for any working you need.

13 9626/12/M/J/19 © UCLES 2019 [Turn over BLANK PAGE

14 9626/12/M/J/19 © UCLES 2019 11 A library database consists of one table containing details of all the books in a library and another table containing details of all the borrowers. Parts of the tables are shown below. Books table 0099445530 0099460874 0439977797 0553812645 0684817306 1857028899 9780593057063 9780593065709 9780593072493 9780752860558 9781780892665 9781846558597 ISBN Title Author Publisher ReplacementCost The Flamboya Tree I Capture the Castle The Tin Princess Ten Thousand Sorrows Kitchen Privileges The Code Book 61 Hours The Affair Inferno Sepulchre Cross Justice Midnight Sun Clara Olink Kelly Dodie Smith Philip Pullman Elizabeth Kim Mary Higgins Clark Simon Singh Lee Child Lee Child Dan Brown Kate Mosse James Patterson Jo Nesbo Bow Books Archaic Panda Books Welter Books Grimon & Custer Quatre Domaine Crossearth Publishers Crossearth Publishers Crossearth Publishers Nebula Books Panda Books Panda Books €7.99 €5.99 €5.99 €6.99 €12.99 €8.99 €18.99 €18.99 €20.00 €18.99 €20.00 €9.99 Borrowers table 1 2 3 4 5 6 7 8 9 10 ID FamilyName FirstName Mobilephone Residence Gale Brown Leadbetter Hull Greenhalgh Pooley Chalmers Lewis Patel Gopaul Henry Kurtis Clementine Christine Karla Fred Ben Christopher Rio Ruksana 07700 900102 01134 960675 01144 960975 07700 900643 08081 570372 09098 790876 01154 960987 07700 900152 08081 570976 03069 990967 Midtown Cheswick Chorlton Denby Portlarne Midtown Denby Denby Chorlton Cheswick

15 9626/12/M/J/19 © UCLES 2019 [Turn over (a) You have been asked to create a query which will output only the names and phone numbers of all the borrowers who have a family name beginning with G and also live in Midtown. Describe the steps you would have to follow in order to create this query, without using a query wizard or a parameter query. … … … … … … … … … … … …[5]

16 9626/12/M/J/19 © UCLES 2019 (b) You have been asked to create a query which will output only the titles and authors of all the books published by Panda Books which have a replacement cost of less than €20. (i) Describe the steps you would have to follow in order to create this query, without using a query wizard or a parameter query. … … … … … … … …[3] (ii) Describe how you would set up the query in (b)(i) as a parameter query. … … … … … … … …[3]

17 9626/12/M/J/19 © UCLES 2019 [Turn over (c) Explain why the above tables (on page 14) do not constitute a relational database and what would need to be added to make them so. … … … … … … … …[3]

18 9626/12/M/J/19 © UCLES 2019 12 Validation is often used to check that data entered into a computer is sensible. A customer orders database contains details of the Customer ID number, the value of the order placed and the date the order was placed. Any new order, when it is entered, needs to be validated. Using these examples of database fields, analyse the use of the following different validation rules – range check, type check, length check and format check. … … … … … … … … … … … … … … … … … … … …[8]

19 9626/12/M/J/19 © UCLES 2019 13 Many driving schools are asking IT companies to develop simulators for teaching customers to drive. Evaluate the development of simulators for this purpose. … … … … … … … … … … … … … … … … … … … …[8]

20 9626/12/M/J/19 © UCLES 2019 Permission to reproduce items where third‑party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. To avoid the issue of disclosure of answer‑related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cambridgeinternational.org after the live examination series. Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge. BLANK PAGE

This document consists of 11 printed pages. © UCLES 2019 [Turn over Cambridge Assessment International Education Cambridge International Advanced Subsidiary and Advanced Level INFORMATION TECHNOLOGY 9626/12 Paper 1 Theory May/June 2019 MARK SCHEME Maximum Mark: 90 Published This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers. Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge International will not enter into discussions about these mark schemes. Cambridge International is publishing the mark schemes for the May/June 2019 series for most Cambridge IGCSE™, Cambridge International A and AS Level and Cambridge Pre-U components, and some Cambridge O Level components.

9626/12 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2019 © UCLES 2019 Page 2 of 11 Generic Marking Principles These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these marking principles. GENERIC MARKING PRINCIPLE 1: Marks must be awarded in line with: • the specific content of the mark scheme or the generic level descriptors for the question • the specific skills defined in the mark scheme or in the generic level descriptors for the question • the standard of response required by a candidate as exemplified by the standardisation scripts. GENERIC MARKING PRINCIPLE 2: Marks awarded are always whole marks (not half marks, or other fractions). GENERIC MARKING PRINCIPLE 3: Marks must be awarded positively: • marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the scope of the syllabus and mark scheme, referring to your Team Leader as appropriate • marks are awarded when candidates clearly demonstrate what they know and can do • marks are not deducted for errors • marks are not deducted for omissions • answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the question as indicated by the mark scheme. The meaning, however, should be unambiguous. GENERIC MARKING PRINCIPLE 4: Rules must be applied consistently e.g. in situations where candidates have not followed instructions or in the application of generic level descriptors. GENERIC MARKING PRINCIPLE 5: Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may be limited according to the quality of the candidate responses seen). GENERIC MARKING PRINCIPLE 6: Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or grade descriptors in mind.

9626/12 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2019 © UCLES 2019 Page 3 of 11 Question Answer Marks 1 It is often referred to as public key encryption 9 It uses a pair of keys, a public key and a private key 9 The public key and the private key are published to everyone who wants to send a message Anyone with a copy of the public key can read encrypted data It is possible to deduce the private key from the public key SSL is a protocol that uses asymmetric encryption 9 Keys used in symmetric encryption are longer, compared to asymmetric keys Asymmetric encryption is slower to convert than symmetric encryption and requires far more processing power 9 Digital certificates are not used with asymmetric encryption The use of asymmetric key algorithms always ensures security of a message 4 Question Answer Marks 2 A virus corrupts files but does not delete them Ransomware continually deletes files until a ransom is paid One purpose of releasing a worm is to occupy as much bandwidth in a network as possible 9 Ransomware is often initiated by means of a trojan horse 9 A trojan horse is a type of malware within an e-mail attachment that is downloaded without the user understanding the consequences 9 Spyware is a type of software that removes key loggers from a hard disk Adware is additional software attached to a virus when it is downloaded Malicious bots are never used to instigate a SPAM attack A rootkit enables a hacker to gain administrator rights in a victim’s computer 9 A trojan horse just enables a virus to be transmitted as it never deletes data itself 4

9626/12 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2019 © UCLES 2019 Page 4 of 11 Question Answer Marks 3 Five from: Place sensors upstream and downstream from the factory Temperature / light / turbidity sensors would be connected to computer (Analogue) data is converted into digital using an analogue to digital converter / ADC Conversion / use of ADC enables the computer to understand the data Computer receives data from sensors / ADC Readings from above the factory are compared with those from below the factory by the computer Differences / results are printed out / displayed on screen Graphs are automatically produced by the computer showing values from below and above the factory Computer stores readings in a table ready for processing. 5 Question Answer Marks 4 Four from: Max three from: Data consists of raw facts and figures as it does not have any meaning until it is processed and given a context Information is data that is assigned a meaning / presented within a context that gives it meaning, relevance and purpose Knowledge is know-how and learning of contextualised information Max three from: The example does not have a meaning / context The context could be they form an IP address which makes this information Only when it is apparent that IPv4 addresses always consist of four numbers separated by full stops and each number must be between 0 and 255 does this become knowledge Or equivalent statements for their own example (1 for example explained as data, 1 for context explained, 1 for explanation of how it can become knowledge). 4

9626/12 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2019 © UCLES 2019 Page 5 of 11 Question Answer Marks 5(a) Two from: To enable organisations to communicate over a large area securely To enable employees to transmit data securely To enable employees to access the company’s computer network remotely / from home securely To restrict which external users are able to use the company’s network To restrict the resources the external user is permitted to use. 2 5(b) Four from: This process is called tunnelling as it uses a secure means to tunnel through a publicly accessible network It uses encryption « « involves the use of private and / or public keys « « scrambles data so that only the key holder can decrypt / understand it « data remains encrypted throughout transmission and is only decrypted at the destination computer It can use IPsec « « is a network protocol suite that encrypts packets of data sent over a network « « protects data flows between a pair of hosts (host-to-host) / between a pair of security gateways (network-to-network) / between a security gateway and a host (network-to-host) It uses a firewall « « which (monitors and) controls the incoming and outgoing network traffic « « establishes a barrier between a trusted, secure internal network and another outside network or computer It uses authentication, authorisation, and accounting / AAA « « AAA server is a program that handles user requests for access to computer resources « « AAA server typically interacts with network access and gateway servers / with databases and directories containing user information It can use TLS / SSL « « uses asymmetric encryption to establish the session « « symmetric encryption for the main conversation. 4

9626/12 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2019 © UCLES 2019 Page 6 of 11 Question Answer Marks 6 Six from: Legislators Two from: Local government representatives would no longer have to attend a meeting far from their home leading to savings in travel expenses Representatives can take part in and observe a meeting happening in more than one location Problems with video transmissions could lead to misunderstandings / delays in passing laws Saves the task of booking a room for a meeting Business people Two from: Do not have to pay for air / train tickets / car running costs to meet with customers Do not have to pay for hotel accommodation to meet with customers Saves the cost of hiring a venue for a meeting When vital workers in a business have to travel, the business is left short- handed, possibly for days Flight cancellations, airport delays, traffic jams will no longer be reasons or excuses for missing meetings and conferences Can increase productivity as a worker who has a sick child, for example, may be able to hold an important meeting even if they have to stay home for the day Workers can easily share a word-processed document / spreadsheet with a manager Much less personal interaction Television news presenters Two from: • Can hold discussions with more than one person who normally would not travel just for an interview • Can speak with correspondents based in different countries simultaneously • Do not have to wait for eye-witnesses to travel to the tv centre • Presenters do not have to travel to dangerous areas • Interviewees do not have to travel and risk arrest / terrorists / attack. 6

9626/12 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2019 © UCLES 2019 Page 7 of 11 Question Answer Marks 7(a) A primary key is a field in a table which is unique and enables you to identify every record in that table. 1 A foreign key is used to link tables together and create a relationship / it is a field in one table that is linked to the primary key in another table. 1 A compound key is a primary key that combines more than one foreign key to make a unique value. 1 7(b) Three from: Prevents the entry of duplicate data Prevents records being added to a related table if there is no associated record in the primary table Prevents the changing of values in a primary table that result in orphaned records in a related table Prevents the deletion of records from a primary table if there are matching related records. 3 Question Answer Marks 8 Advantages – Two from: The bank will have an electronic copy of the cheque to refer in case of customer complaints Can read all the data on the cheque / not limited to MICR characters Cheques can be processed after being deposited at ATMs Cheques can be processed having been sent by phone (camera) Disadvantages – Two from: Cheques will be easier to forge / less secure New OCR equipment / software will need to be purchased If cheques are written over OCR will not be able to read it OCR is less accurate than MICR. 4 Question Answer Marks 9 Five from: Knowledge base consists of a database of facts / factual data and a rules base Inference engine uses the rules base to reason through the symptoms Inference engine uses the data or facts in the knowledge base to reason through the symptoms Inference engine compares symptoms to those in the knowledge base Inference engine uses the rules base of IF«THEN« rules / comparisons Knowledge base editor enables the knowledge engineer to edit rules and facts within the knowledge base. 5

9626/12 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2019 © UCLES 2019 Page 8 of 11 Question Answer Marks 10(a) =INT((G$2-C4)/365.25) INT() 1 (G$2 1 -C4) 1 /365.25 1 10(b)(i) 16 1 4 1 10(b)(ii) 16 1 3 1 10(c) =COUNTIFS(D4:D23,17,E4:E23,3) =COUNTIFS() 1 (D4:D23 1 ,17, immediately after D4:D23 1 E4:E23 (and must come) after D4:D23 within same function 1 ,3) immediately after E4:E23 within the same function as D4:D23 1 10(d) =COUNTIFS(D4:D23,16,E4:E23,4) =COUNTIFS(D4:D23«.) 1 ,16,E4:E23 1 ,4) immediately after E4:E23 1

9626/12 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2019 © UCLES 2019 Page 9 of 11 Question Answer Marks 11(a) Five from: Select query design In the table row select Borrowers/add Borrowers table In the field row, select the fields FamilyName, FirstName, Mobilephone and Residence In Show row untick Residence In criteria row under FamilyName enter Like G* In criteria row under Residence enter Midtown 5 11(b)(i) Three from: Select query design, in the table row select Books/add Books table and in the field row, select the fields Title, Author, Publisher and ReplacementCost In Show row untick Publisher and ReplacementCost In criteria row under Publisher enter Panda Books In criteria row under ReplacementCost enter <20 3 11(b)(ii) Three from: Select query design Use of [ ] in either prompt In criteria row under Publisher enter [appropriate prompt] In criteria row under ReplacementCost enter [appropriate prompt]. 3 11(c) Three from: There is no field in the Borrowers table which contains similar data to any field in the Books table A field needs to be added to the Borrowers table containing the ISBN number of the book borrowed A link / relationship would need to be created between ISBN number in the Books table and this new field in the Borrower table ISBN in the borrowers table will be the foreign key Or a field needs to be added to the Books table containing the ID of the borrower A link / relationship would need to be created between ID in the Borrowers table and this new field in the Books table ID in the books table will be the foreign key. 3

9626/12 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2019 © UCLES 2019 Page 10 of 11 Question Answer Marks 12 Eight from: Max Five from: A range check is used to check that data is within the boundaries of a given range and could be used on the value of the order placed / the date the order was placed Data must be greater than a lower limit and less than an upper limit / day must be greater than 0 and less than 32 / month must be greater than 0 and less than 13 / year must be greater than« and less than« (accept any reasonable example) A type check is used to check that data is of the correct data type and could be used on the value of the order placed / individual components of the date the order was placed Value of order placed must be numeric / components of date must be numeric A format check is to check that the data is in the correct format and could be used on Customer id number / date order placed Customer ID might be in the form of one letter followed by 6 digits / date order placed might be 2 numbers followed by a dash followed by 2 numbers followed by a dash followed by 4 numbers (accept any reasonable example) A length check is to check that data is of the correct length and could be used on the Customer ID number / date order placed Any reasonable example of a length check Max Five from: A range check would not be appropriate for the Customer ID number as it is likely to consist of alphanumeric characters A range check would trap any values outside the range but might not pick up transposition errors A type check would not be appropriate on Customer ID number as the values might not solely consist of digits A type check would trap letters typed instead of numbers but might not pick up values outside a range or transposition errors A format check would not be appropriate on value of order placed as the values in the numeric part might vary in length considerably A format check would trap incorrect formats but might not pick up transposition errors A length check would not be appropriate on value of order placed as the values might vary in length considerably A length check would check the correct length of the data item but would not pick up data of the wrong format or transposition errors. 8

9626/12 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2019 © UCLES 2019 Page 11 of 11 Question Answer Marks 13 This question to be marked as levels of response: Level 3 (7–8 marks) Candidates will include the advantages and disadvantages of simulations. The information will be relevant, clear, organised and presented in a structured and coherent format. There may be a reasoned conclusion / opinion. Specialist terms will be used correctly and appropriately. Level 2 (4–6 marks) Candidates will include the advantages and disadvantages of simulations. Although development of some of the points will be limited to one side of the argument. For the most part, the information will be relevant and presented in a structured and coherent format. Specialist terms will be used appropriately and for the most part correctly. Level 1 (1–3 marks) Candidates will present advantages or disadvantages of simulations. There will be little or no use of specialist terms. Answers may be simplistic with little or no relevance. Level 0 (0 marks) Response with no valid content. Examples may include: Advantages: Driving schools can test all aspects of driving without worrying about damaging an expensive car Can provide results that are generally difficult to measure such as reaction times Computer simulation can allow you to see how a system might respond before you design or modify it avoiding mistakes It is safer to use a model and simulation for car driving Can be slowed down to study behaviour more closely Is easier to create a simulation of a critical event rather than waiting for it to happen in real life Is easier to create a simulation of different driving conditions rather than waiting for it to happen in real life Disadvantages: Sometimes there is not sufficient data to produce a mathematical model Sometimes it is impossible to create simulations that can accurately predict the occurrence / effects of human behaviour The formula and functions that are used may not provide an accurate description of the system resulting in inaccurate output from the simulation Sometimes simulations can require the use of a computer system with a fast processor and large amounts of memory which are very expensive May give drivers a false sense of security regarding their ability to drive. 8