NASS S4 2022 Prelim P1 MS

Name: Register no: Class: NGEE ANN SECONDARY SCHOOL O Marking Scheme PRELIMINARY EXAMINATION COMPUTING 7155/01 Paper 1 Written 25 August 2022 2 hours Candidates answer on the Question Paper. No Additional Materials are required. Instructions to Candidates Write your name, register number and class at the top of this page. Answer ALL questions. Write in dark blue or black pen. You may use pencil for any diagrams, graphs, tables or rough working. The use of an approved scientific calculator is expected, where appropriate. The number of marks is given in brackets [ ] at the end of each question or part question. You should show all your working. The total number of marks for this paper is 80. Checked by student: _____________________ Date: ______________ For Examiner’s Use

2 NAS/2022/PRELIM/4E/COMPUTING(7155/01) This document consists of 16 printed pages and 2 blank pages. 1 (a) The bus topology and the star topology are two possible physical layouts of a network. Give one feature that is the same for both a bus topology and a star topology, and one difference between the two. Feature that is the same: Both networks can still continue to operate even when one of the computers breaks down. The replacement can be done without affecting the rest of the network. [1] Difference: Setting up a star topology typically costs more as it uses more cabling as compared to a bus topology which is easy and cheap to install as it uses less cabling. [1] [2] (b) A home network typically requires a network interface controller and a router. Identify and describe the function of one other network device that could be part of the home network. Device: Modem [1] Function: A modem is responsible for modulation and demodulation which is the conversion of digital data into a form suitable for transmission and vice versa. [1] [2]

3 NAS/2022/PRELIM/4E/COMPUTING(7155/01) 2 Ms Anna attempts to use a spreadsheet to record the gender ratio of each class. She records: • the number of girls and boys in each class • the ratio of girls to boys in each class • the classes Upon keying the ratio from cells C2 to C4, the spreadsheet detects the input and automatically changes the data type into something other than the expected ratio. (a) Identify the data type which cells C2 to C4 are changed into. TIME [1] [1] (b) Describe how Ms Anna can make the spreadsheet display the expected ratio. She can select cells C2 to C4 [1] and change their data type into TEXT [1]. OR she can type in an apostrophe in front of the data [1] like this: '20:20 [1] describe + example [2] (c) Cell D2 needs to show the percentage of girls in each class. Identify the most appropriate function that will need to be entered into D2 and copied to cells D3 and D4. =A2/SUM(A2,B2) [1] [1] (d) Cell E6 needs to show a boolean value which indicates if the number of boys in class A is more than the number of girls in class A and more than the combined total number of boys from the other two classes. Identify the most appropriate function that will need to be entered into E6. =IF(AND(B2>SUM(B3,B4),B2>A2),TRUE,FALSE) [1 for IF 1 for AND with correct conditions] [2]

4 NAS/2022/PRELIM/4E/COMPUTING(7155/01) (e) Cell E7 needs to show the class with most number of girls. Identify the most appropriate function that will need to be entered into E7. =VLOOKUP(MAX(B2:B4),B2:E4,4,FALSE) [1 for max, 1 for vlookup] [2] 3 Devon is developing a single-player computer game. The objective of the game is to harvest as many crops as possible within a time limit in order to score the most number of points possible. The player is able to customise the look of the sprite, and buy any tools that can help to speed up the process of harvesting before the start of the game using the points the player has accumulated. The game will save the points achieved by the player after every round. Before the program is written, Devon decomposes the problem using a modular approach. (a) Describe what is meant by a modular approach. [2] In a modular approach, we will solve simple examples of the problem manually and identify the tasks that are of different natures. [1] These tasks can usually be separated from each other to become distinct sub-problems that are different from each other. [1] (b) One of the modules is to save the points achieved by the player after each round. Identify three other modules that can be decomposed from the problem. [3] Module 1: This module includes options for player to change the appearance of the sprite in the program. [1] Module 2: This module includes a variety of tools for the player to purchase to enhance his harvesting speed. / This module has an interface that displays the tools available for purchase. [1] (or module to track the harvesting speed of player based on tools he has) Module 3: This module keeps track of the running time during each game and ends game once time is up. [1]

5 NAS/2022/PRELIM/4E/COMPUTING(7155/01) (c) Devon eventually completes writing the code as well as testing and refining the code. Describe the remaining stage of program development that is necessary for him to complete the program development. [2] The final stage is to deploy the code. [1] This is the stage where the game program is “rolled out” to the intended audience and he will inform users on how to play the game and gather any further feedback for improvement. [1] 4 A local bank has recently developed a mobile application that allows its users to make digital payments by scanning a QR code when shopping overseas. The user can review the price in either currency before confirming payment. (a) State and explain one positive impact that this mobile application may have on businesses. Increase sales as it provides convenience for its customers from other countries. OR As the payment is done digitally, businesses will be able to reduce cost and effort needed for payments. [1] [1] (b) Transaction data from payment applications could be analysed further with Artificial Intelligence (AI) to benefit the user. Describe how transaction data from such a mobile application can be analysed further with AI. The transaction data from this mobile application can be analysed with Artificial Intelligence to reveal spending patterns or habits[1], so as to suggest possible items that my interest the user for purchase[1]. OR The transaction data from this mobile ap plication can be analysed with Artificial Intelligence to identify unusual spending patterns [1], so as to automatically detect financial fraud. [1]. [2] (c) Payment using mobile application is often accompanied with biometric authentication. Explain the benefit of using biometric authentication when making payment. Biometric authentication is based on the measurement of human physical characteristics such as fingerprint or iris. [1] As it cannot be easily replicated and is easily accessible by the user, it provides a quick and secure way to authenticate the user during payment. [1] [what is it, benefits of it + linking to qns] [2]

6 NAS/2022/PRELIM/4E/COMPUTING(7155/01) 5 A ransomware attack typically works by tricking a target into clicking a malicious link by using a fake email that appears to be from reputable companies. (a) State another form of cyberattack which works in a similar way. Phishing [1] [1] (b) Once the attackers have access to critical files on the computer, they