SPSS 2018 P1

READ THESE INSTRUCTIONS FIRST Write your name, class, index number 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 or graphs. Do not use staples, paper clips, glue or correction fluid. Approved calculators are allowed. Answer all questions. 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. Parent’s Signature : ____________________________ Date: ____________________________ Remarks (if any) : For Examiner’s Use Marks /80 Total % This document consists of 14 printed pages including this page. ST. PATRICK'S SCHOOL PRELIMINARY EXAMINATIONS 2018 SECONDARY 4 EXPRESS NAME CLASS INDEX NUMBER COMPUTING Paper 1 Written 7155/01 11 September 2018 2 h Candidates answer on the Question Paper. No Additional Materials are required.

2 [Turn over 1 Draw a line to match the spreadsheet function to the correct description. Function Description MAX Returns the most frequently occurring or repeated value in the given numbers or the given range/cell references LARGE Returns a user-defined number of characters starting from a position of the text value text MODE.SNGL Returns the largest number out of the given numbers or the numbers in the given range/cell references Returns the kth largest number in a range of cells [3] 2 (a) Convert the binary number 10110110 into a denary number. Show your working. [2] (b) Convert the hexadecimal number F5 into a binary number. Show your working. [2] (c) Convert the denary number 34 into a hexadecimal number. Show your working. [2]

3 [Turn over 3 Insert six of the following words about computer hardware, memory and storage devices in the correct place in the respective spaces below. optical storage(s) digital storage(s) solid-state storage(s) processor register(s) ROM RAM ALU secondary storage(s) address bus(es) data bus(es) control unit(s) The type of memory or storage employed in a computer depends on how the data stored inside is meant to be used: are physically located inside the processor. The extremely fast but small data storage spaces are used directly by the and . or main memory is where data and instructions are stored temporarily so that they can be quickly accessed by the processor when needed. is where data and instructions that rarely need to change or would be needed for a computer to start up are stored. is where large amounts is where large amounts of data are stored, such as in a hard disk or a hard drive. . [6] 4 Signals are sent to and from the components of a processor using buses. Identify and describe the purpose of two different buses. (a) Bus 1 Purpose [3] (b) Bus 2 Purpose [3]

4 [Turn over 5 Programmers would usually use programming language rather than machine code to write a computer program. (a) Explain what is meant by “high-level programming language”. [1] (b) A program written in a high-level programming language is translated into machine code. This is so that it can be processed by a computer. Name one type of translator that can be used. [1] (c) Briefly describe how your answer to part (b) translates this program. [1] (d) State one advantage of your answer to part (b) as compared to other type(s) of translators. [1] 6 A company wants to use a computer program to find out which employee has secured the biggest contract in the year 2017. There are 50 employees in the company and all the contracts’ amounts are different. State the inputs, the outputs and the processes required to find the name and the contract amount of that employee. Inputs Outputs Processes required [6]

5 [Turn over 7 An algorithm is required to check that the user has entered a Personal Identification Number (PIN) that is 5 digits long. The input is provided in an integer called “PIN” and the output is displayed on the screen. Study the following pseudo-code. count INPUT PIN REPEAT PIN = PIN%10 count = count + 1 UNTIL PIN >= 1 IF PIN == 5 THEN OUTPUT “PIN length is valid.” ELSE OUTPUT “PIN length is invalid.” ENDIF There are four errors in this pseudo-code. Locate the errors and state the correct pseudo-code. Error 1 Correction Error 2 Correction Error 3 Correction Error 4 Correction [8]

6 [Turn over 8 An online-banking user was checking his email’s spam mailbox when he noticed that he received the following notification allegedly from DBS Bank. The user promptly recognizes that the email is fraudulent and ignores it after a quick scrutiny. (a) Name and explain the type of cyberattack involved. [2] (b) Identify two tell-tale signs that allowed the user to conclude that the email is fraudulent. Sign 1 Sign 2 [2]

7 [Turn over 9 A company has several offices around the world. (a) Data is transmitted between the offices over the Internet. In order to keep the data safe the company is using a firewall at each office. Explain how a firewall would keep the company’s data safe. [2] (b) The use of firewall alone is clearly not sufficient to ensure safety of the company’s sensitive data. Suggest, with reasons, three other security measures that the company should take to keep their sensitive data safe. Measure 1 Measure 2 Measure 3 [3] 10 The following is an example of a Uniform Resource Locator (URL). http://stpatricks.moe.edu.sg/contact-us.htm Identify the three parts that make up the URL. Part 1 Part 2 Part 3 [3] Part 1 Part 2 Part 3

8 [Turn over 11 This flowchart shows a program, which accepts an input list of numbers and sorts them accordingly. The sorted list is then returned as the output. START i = 0 j = 0 INPUT num_list Is i < (length of num_list) Is j < (length of num_list) - 1 Is num_list[j] < num_list[j+1] temp = num_list[j] num_list[j] = num_list[j+1] num_list[j+1] = temp j = j+1 i = i+1 j = 0 OUTPUT num_list STOP YES YES NO NO YES NO

9 [Turn over Complete the trace table for the following set of data. num_list = [4, 2, 7, 9] Trace table i j temp num_list[j] num_list[j+1] OUTPUT 0 0 1 2 7 2 2 2 9 2 1 0 4 7 4 1 4 9 4 2 2 0 7 9 7 1 2 3 0 1 2 [9, 7, 4, 2] [6]

10 [Turn over 12 Complete the truth table and name the single logic gate that could replace the logic circuit. Single logic gate A B Working Space X 0 0 0 1 1 0 1 1 [2] [1] 13 An indicator light will switch on when certain conditions occur in a laboratory. The output, X, of a logic circuit that drives the indicator light must have a value of 1 only if: either temperature (A) is high and humidity (B) is low or humidity (B) is high and pressure (C) is low The inputs to the system are: Input Binary Condition A 0 Temperature is low 1 Temperature is high B 0 Humidity is low 1 Humidity is high C 0 Pressure is low 1 Pressure is high (a) Complete the Boo