Computer Studies Questions and Answers - KCSE 2022 Pavement Form 4 Trial 1 Pre-Mock Examination

QUESTIONS

1.                      
   1.  A computer laboratory should be constantly kept dust and smoke free.
      Specify two effects that dust would have on the operation of computers. (2 marks)
   2. Why should you first switch on the UPS before switching on the system unit and the monitor? (2 mark)
2. Explain the meaning of backup. (2 marks)
3. State the following types of transcription errors. (2 marks)
   1. 3455 instead of 3456
   2. Smith instead of simth
4.                      
   1. State three ways used to represent a negative number. (3 marks)
   2. Perform the following binary arithmetic giving the answer in decimal notation.
      1110.0111 + 1101001.011 (2 marks)
5. Distinguish between data privacy and data integrity as used in computing. (2 marks)
6. Differentiate between a primary key and a foreign key while designing a database. (2 marks)
7. Distinguish between ‘count’ and ‘count if’ functions as used in spreadsheets. (2 marks)
8. Explain the impact of Information Technology on organization in each of the following areas. (2 marks)
   1. Competition.
   2. Pace of growth.
9. List two roles performed by system analyst. (2 marks)
10. Explain the following internet related terms. (4 marks)
    Sign IN
    Search engine
    Surf
    Sign up
11. In Kenya Tea Packers Company, several people are employed as record clerks, typists and messenger. The company intends to introduce a computerized system in all the departments. Suggest three reasons that would make workers unhappy with the new system. (3 marks)
12. State two magnetic Storage devices. (2 marks)
13. State three functions of Central Processing Unit. (3 marks)
14. Explain two ways of protecting data and information in a database against unauthorized access (2marks)
15.                              
    1. Name two ways in which data can be input into a computer, and state the device that can be used in each case. (2mks)
    2. Explain why a buffer is used in the output of data to a line printer (1mk)

SECTION B
(Answer question 16 and any other three questions from this section)

16.                      
    1.  List two programming language translators. (2mks)
    2. State three advantages of using low level programming languages. (3mks)
    3. Give two methods you would use in error detection during program testing. (2mks)
    4.                        
       1. Study the flowchart below and write a pseudo-code for the flowchart. (7mks)
          
       2. Name the control structures used in the flow chart above. (1mks)
17.                            
    1. Explain any THREE functions of system software in a computer (3mks)
    2. As a computer student you have been asked to assist in buying an input device. State any four factors to consider when buying input devices. (4mks)
    3. Explain three problems associated with using e-mail technology for communication. (6mks)
    4. State three advantages of integrated software as opposed to single purpose. (3mks)
18.                              
    1. List and describe four strategies for converting from an old system to a new system. (4mks)
    2.                  
       1. Distinguish between private data and confidential data. (2mks)
       2. What can be done to stop illegal access to a computer laboratory by unauthorized people? (3mks)
          1. List four areas that would be considered in the requirement specification. (4mks)
          2. Name any two areas covered in feasibility report during system analysis and design. (2mks)
19.                            
    1. What is the hexadecimal equivalent of 7678 (3mks)
    2. Use one’s compliment to solve the following sum: -510 (2mks)
    3. Compute the values of X in the following expressions
       1. 24.35₁₀ = X₂
       2. 6A13_H = X₁₀ (2mks)
    4. Using two’s complement compute (5mks)
       36₁₀ – 25₁₀
20.                                        
    1. On her first day at work as a school librarian, Sera notices that book records are kept manually using a card system. She suggests to the Principal that they use a database. State three reasons why using a database would be helpful to the librarians (3mks)
    2. Give four examples of DBMS programs which could be used. (2mks) Lotus
    3. The manager of Pacific Company Ltd uses a database to keep records of his employees as shown in the table below. Use this information to answer the questions that follow.
       
       
       1. Name and explain the appropriate data type for
          ID: (1mk)
          Age: (1mk)
          Salary (1mk)
       2. Write a query expression to display details of employees working in the Administration department (3mks)
    4. The function =AVERAGE (B2:B8) in cell B9 has been copied and pasted to cells C9 to K9 in spreadsheet.
       1. What would be the formula at cell D9 (2mks)
       2. Explain the type of cell referencing used in the above formula (2mks)

MARKING SCHEME

1.                      
   1.  A computer laboratory should be constantly kept dust and smoke free.
      Specify two effects that dust would have on the operation of computers. (2 marks)
      
      • Dust may cause malfunction of read/write heads of the drive
      • Dust May cause failure of a fan that cools the processor
   2. Why should you first switch on the UPS before switching on the system unit and the monitor? (2 mark)
      Because the computer get power from the UPS
2. Explain the meaning of backup. (2 marks)
   
   • Making of copies of data, programs incase the originals are corrupted or lost
   • It is used to protect data from accidental erasure or hardware problems
3. State the following types of transcription errors. (2 marks)
   1. 3455 instead of 3456
      
      • Misreading errors
   2. Smith instead of simth
      
      • Transposition
4.                      
   1. State three ways used to represent a negative number. (3 marks)
      
      • Ones complement
      • Twos complement
   2. Perform the following binary arithmetic giving the answer in decimal notation.
      1110.0111 + 1101001.011 (2 marks)
      

      1110.0111
      1101001.0110 +
      110111.1101
      119.8125 or 119¹³/₁₆

5. Distinguish between data privacy and data integrity as used in computing. (2 marks)
   
   • Data privacy -keep data secretly so that unauthorized people don't access it
   • Data integrity- correctness, completeness and accuracy of data
6. Differentiate between a primary key and a foreign key while designing a database. (2 marks)
   
   • Primary key-unique field that identifies a record in a database
   • Foreign key-a primary key in another table once the tables are linked
7. Distinguish between ‘count’ and ‘count if’ functions as used in spreadsheets. (2 marks)
   
   • Count- counts cells that contain values in a range of cells
   • Count if- counts cells that meet a given criteria in a range of cells.
8. Explain the impact of Information Technology on organization in each of the following areas. (2 marks)
   1. Competition.
      
      • Ability to advertise on the internet
      • Improve quality of goods
      • Reduced operational cost
   2. Pace of growth.
      
      • Reduced cost
      • Reduced need for man power
      • Reduced space requirement
      • Greater output
9. List two roles performed by system analyst. (2 marks)
   
   • Analyses and assesses suitability of a system for computerization
   • Programmers builds on the analyst results to create a new computer based system
   • Trains staff on the new system
   • He collects facts from the users
   • Works hand in hand with programmers to create a new computer based program
10. Explain the following internet related terms. (4 marks)
    
    • Sign IN - Enter user name and password to authenticate the access to e-mail account
    • Search engine -Site used for searching material from the internet
    • Surf - Browsing or accessing internet resources.
    • Sign up - Registering to have an account for e-mail or other communication media
11. In Kenya Tea Packers Company, several people are employed as record clerks, typists and messenger. The company intends to introduce a computerized system in all the departments. Suggest three reasons that would make workers unhappy with the new system. (3 marks)
    
    • Job replacement
    • Retraining on use of computers
    • Side effect of using computer
    • Loss of status Quo
12. State two magnetic Storage devices. (2 marks)
    
    • Hard disk
    • Floppy disk
    • Jaz disk
    • Zip disk
    • Magnetic tape
13. State three functions of Central Processing Unit. (3 marks)
    
    • Control the use of the main memory in storing data & information
    • Processing and manipulation of data into useful information
    • Manages execution of instructions
    • Give commands to all parts of the computer
    • Control the sequence of operations within the computer
14. Explain two ways of protecting data and information in a database against unauthorized access (2marks)
    
    • Password protection – A password to open or exit the database file i.e. let’s any user who wishes to do any action.
    • Data encryption – If the database is to be sent electronically encryption secures the data from un authorized access
    • User and group permission to users on data base object such as queries form and reports
    • User level security – this feature is used to assign permission to users in order to limit user access to certain database object
15.                              
    1. Name two ways in which data can be input into a computer, and state the device that can be used in each case. (2mks)
       
       • Console input (keyboard)
       • Voice input –(microphone)
    2. Explain why a buffer is used in the output of data to a line printer (1mk)
       

       To store information temporarily to cope with the difference in speeds of the various        peripherals (input / output) devices.

SECTION B
(Answer question 16 and any other three questions from this section)

16.                      
    1.  List two programming language translators. (2mks)
       
       • Assemblers
       • Compilers
       • Interpreters
    2. State three advantages of using low level programming languages. (3mks)
       
       • Program execution is immediate
       • They require no compilation, no interpretation/ translation hence they are faster.
       • Hardware optimization is extensive
       • Program developed takes less memory space
       • Suitable for micro devices
       • Easy to design electronic device
    3. Give two methods you would use in error detection during program testing. (2mks)
       

       Use of disk checking
       Using debugging utilities
       Using test data

    4.                        
       1. Study the flowchart below and write a pseudo-code for the flowchart. (7mks)
          
          PSEUDO CODE
          

          START

          Input A,B,C

          Calculate Sum = A+B+C

          IF SUM > 200 THEN

                SUM = SUM – 30

          ELSE

                SUM= SUM + 20

          ENDIF

          PRINT SUM

          STOP

       2. Name the control structures used in the flow chart above. (1mks)
17.                            
    1. Explain any THREE functions of system software in a computer (3mks)
       
       • Supports the development of other application software.
       • Supports the execution of other application software.
       • Monitors the effective use of various hardware resources e.g. CPU, memory, peripherals etc.
       • Communicates and controls the operation of peripheral devices such as a printer.
       • Performs a variety of system utility functions
    2. As a computer student you have been asked to assist in buying an input device. State any four factors to consider when buying input devices. (4mks)
       
       • Type of data to be input -
       • user friendliness
       • Speed of the input device
       • Volume of data
       • Accuracy of the input device
       • Cost of the device
       • Availability of the device
    3. Explain three problems associated with using e-mail technology for communication. (6mks)
       
       • Threat to privacy
       • Organization ‘System admn’ can snoop into people mail.
       • Email can be unsolicited/spam mail.
       • Messages can be sent to masses of people without their consents
       • Vulnerability of machine failures
       • Emails can be overwhelming when many messages are received leading email overloading and going through each of them can be taxing.
       • Email can be faked.
       • Email attached can be a source of viruses.
       • Email technology not available to all/technology illiteracy.
       • Encourage illicit communication such as immoral behavior
    4. State three advantages of integrated software as opposed to single purpose. (3mks)
       
       • Takes shorter time to install
       • Error free since they are thoroughly tested.
       • They are readily available for almost all the tasks
       • The integrated software is compatible and has common features so easy to learn
18.                              
    1. List and describe four strategies for converting from an old system to a new system. (4mks)
       
       • Direct approach- user simply stops using old system and starts using the new one
       • Parallel approach- old and new system is operated side by side until the new system has shown it is reliable.   
       • Phased approach -parts of a new system are phased in separately either at different times or all at one in groups
       • Pilot approach- entire system is tried out but only by some users
    2.                  
       1. Distinguish between private data and confidential data. (2mks)
          
          • Private data – belongs to an individual and must be accessed through direct permission from the owner
          • Confidential data – held by government or organization about people but can be seen by authorized people only.
       2. What can be done to stop illegal access to a computer laboratory by unauthorized people? (3mks)
          
          • Fit strong metallic grills and locks to doors
          • Don’t welcome strangers into the lab
          • Install alarms
          • Employ guards
          • Burglar proof
          1. List four areas that would be considered in the requirement specification. (4mks)
             
             • Output specification
             • Input specification
             • File /data/tables
             • Hard ware/soft ware
          2. Name any two areas covered in feasibility report during system analysis and design. (2mks)
             
             • Schedule
             • Users
             • Environment
             • Technology
19.                            
    1. What is the hexadecimal equivalent of 7678 (3mks)
       

       Step1convert 767₈ to decimal

       7x 8² + 6x8¹ +7x8⁰

       448+48+7=503₁₀

       Step2
       Convert 503₁₀ to hexadecimal

       16	503	Rem
       16	31	7
       16	1	15
       	1	1

       767₈=IF 7₁₆
       

       Correct method/ step and answer give a mark

    2. Use one’s compliment to solve the following sum: -510 (2mks)
       

       2	5	Rem
       2	2	1
       2	1	0
       	1	1

    3. Compute the values of X in the following expressions
       1. 24.35₁₀ = X₂
          
          
       2. 6A13_H = X₁₀ (2mks)
          
    4. Using two’s complement compute (5mks)
       36₁₀ – 25₁₀
       
       
20.                                        
    1. On her first day at work as a school librarian, Sera notices that book records are kept manually using a card system. She suggests to the Principal that they use a database. State three reasons why using a database would be helpful to the librarians (3mks)
       

       Unnecessary duplication
       Time wastage
       Poor update of records

    2. Give four examples of DBMS programs which could be used. (2mks) 
       approach, Ms access,   ms SQL server, Oracle, DbaseIV
    3. The manager of Pacific Company Ltd uses a database to keep records of his employees as shown in the table below. Use this information to answer the questions that follow.
       
       
       1. Name and explain the appropriate data type for
          

          ID:       text  

          Age:    number  

          Salary  currency
       2. Write a query expression to display details of employees working in the Administration department (3mks)
          

          Select * from table where department=”administration”

    4. The function =AVERAGE (B2:B8) in cell B9 has been copied and pasted to cells C9 to K9 in spreadsheet.
       1. What would be the formula at cell D9 (2mks)
       2. Explain the type of cell referencing used in the above formula (2mks)
          

          Relative cell referencing