KCSE Computer Studies Mokasa Joint Exams Plus Free Marking Schemes

Carry digit ˃

451/1 – COMPUTER STUDIES – Paper 1

2½hrs

MARKING SCHEME

SECTION A (40 MARKS)

ANSWER ALL QUESTIONS IN THIS SECTION

Name the two common types of system units and differentiate them. (2 marks)

Tower
Desktop

Desktop -the monitor is placed on top of the system unit. The tower type the monitor rests on the table

Define the following characteristics of a computer system. (2 marks)

Versatile
Reliable

Versatile– Computers are flexible in that they can be used to carry out different types of activities such as typing, calculations and playing music.

Reliable – Computers are more reliable because they do not get tired or bored in the processing repetitive activities

Digital computers work with digital content. Describe a digital device. (2 marks)

A digital device processes electronic signals that represent either a one (“on”) or a zero (“off”)
A digital deviceis an electronic device that can receive, store, process or send digital information IN discrete formats in binary representation.

Differentiate between third and fourth generation computers (2marks)

Third generation computers used electronic component called Integrated circuits (ICS) which is a single component that consist of thousands of transistors etched on a semiconductor called a Silicon Chip. It emitted less heat, were smaller in size, easier to program and maintain compared to second generation computers
Fourth generation computers used an electronic component called microprocessor. It was designed to allow thousands of transistors embedded into a silicon chip made up very large scale integration(VLSI) giving birth to central processing unit that power microcomputer. Fourth generation computers are characterized by very low emission of heat and are small in size and easier to use and maintain

(a) Mamboleo company is in the process of computerizing its services. List four measures that should be put into consideration to protect the users in their computerized areas. (2marks)

Power cables should be insulated
Providing standard furniture
Proper ventilation
Painting the wall with less reflective paints.
Overcrowding should be avoided.
Give two reasons why powder and liquid extinguishers are not recommended unlike gaseous extinguishers. (2marks)
Liquid –based extinguisher may cause rusting and corrosion of computer components
Powder particles may increase friction, clogging and wearing of movable computer parts

Without proper marketing, a business cannot survive in a competitive environment hence computers are being used in a number of ways to enhance marketing. List any three ways of ensuring this is effected. (3 marks)

Electronic Commerce or e-business
Electronic presentation
Advertising

Differentiate between the following as used in computers. (3 marks)

Tab Key
Spacebar
Clicking

Tab Key– It is used to move the cursor at set horizontal intervals on the same line such as 0.5inch,1.0 inch e.t.c.

Space bar– It is used to insert spaces between characters on words when typing

Clicking– Pressing and releasing the left mouse button once. A click often selects an Icon or Menu.

Control unit is an essential component of the CPU. Describe the functions of the control unit. (2 marks)

The control unit is responsible for coordinating all the activities of the C.P.U
To coordinate these activities, the control unit uses a system clock that sends command signals

(a)Differentiate between buffers and Registers (2 marks)

(i)Buffers are special memories that are found in input/output devices. Input data are held in the input buffer while processed output is held in output buffer.

(ii) A register is located inside the microprocessor hold one piece of data at a time one inside the C.P.U e.g Accumulator, Instruction Register, Address Register and storage register

(b)Speech recognition devices are used to capture natural sound and convert the input into digital form. State two problems related to speech recognition devices. (2 marks)

Recognition rate is slow – the number of words in English and the number of words which can be said at a given point (known as branching factor) mean that response rates are still relatively slow.
Limited vocabularies – most systems are still limited to words in isolation; connected speech is much harder to get right than segmented speech. A computer may not respond to a voice command that has speech related problems like accents, Inflations and varying tones.
Speaker variability–The speed, pitch, range, rhythm. Intonation, loudness and pronunciation of an individual can vary (especially if they a have a cold).
Homophones – Some words e.g. see and sea, sound the same.
Problems of speech context – A computer cannot understand different contexts and meanings of speech because it is ‘literal minded’.
Background noise –Can upset voice input without a shielded mouthpiece on the microphone.

Define Solid-state storage and give two examples. (2 marks)

A non-volatile storage that employ integrated circuits rather than mechanical, magnetic or optical technology. They are referred to solid state because they do not have movable parts in its read/write storage mechanism.

(a) Explain how a pixel affects the resolution of a monitor. (1 mark)

A pixel is the smallest unit of a digital image or graphic that can be displayed and represented on a digital display device. The higher the number of pixel, the clearer and excellent images formed on the screen. Less pixel results to less clearer and poorer display on the screen.

(b) List two types of computer output on microform (COM). (2marks)

Microfiche
Microfilm

Differentiate between high definition multimedia interface and Firewire (2 marks)

High definition interface is an interface used for transmitting digital audio and video data from computer to a projector, TV or audio device.

Firewire It is similar to USB but has a higher transmission rate hence it is suitable for streaming video from digital cameras to a computer

A warranty is an agreement between the buyer and the seller. It spells out terms and conditions after selling a product in case of failure or malfunction. Describe any three basic requirements a good warranty should cover. (3 marks)

Scope of cover for example 4 months, 2years
Callout response and liability agreement. For how long should the supplier take to repair a fault or replace the product and if he/she delays who beams the cost.
Preventive maintenance for example regulating of service at intervals.

(a)Differentiate between pasteboard and master page as used in DTP (2 marks)

Pasteboard: The background that lies behind your document. It is a convenientspace to put things if you need to move text or images between pages. You can also place items on the pasteboarduntil you decide where to position them on the page. Any text or images that you place on the pasteboard won’t be printed.
Master page: A page used in designing the general layout that will be replicated in all other pages in the publication.
Differentiate between graphic-based and layout based desktop publishing software. (2 marks)
Graphic based- They are specifically developed to edit and format graphic objects such as pictures and vector drawings.
Layout based- Are specifically developed to create different page layout designs for text and

Differentiate between Network database and Relational database. (2 marks)

Network – model links are used to express the relationship between different data items, forming a network of items. Access to one item can be through multiple paths and from any item. Used to express the relationship between different data items forming a network of items. Access to one item can be through multiple paths from any item
Relational – Data items are stored together in structures called relations. In Relational database related data items are stored together in structures (relations or tables). Relationship can be created between tables such that a record or records from one table relates to another or other records in another table.

SECTION B (60 MARKS)

ANSWER QUESTION 16 AND ANY OTHER THREE QUESTIONS IN THIS SECTION

(a) Define the following terms as used in programming (2 marks)

(i) Source code

The program instructions entered in the program editor window that is not yet translated into machine readable form (binary language).

(ii) Object code

The program or source code that is already translated into machine readable form (binary language).It is produced by the assembly process (the production of a source code to machine form/binary).

(b) Differentiate between Assembler and Interpreter as used in programming. (2 marks)

Assembler(s) – it is a program or language processor that translates assembly language into machine language that the computer can understand and execute.

Interpreters – It is a translator program that translates source program one instruction at a time, completely translating and executing each instruction before it goes onto the next. Interpreters seldom produce object code but temporarily produce intermediate code which is not stored in main memory.

(i) 1101 1101 1011 1011

1110 0001 1100 0111

0010 1110 1011 0011

Machine Language

………………………………………………………………………………………..………………………

(ii) LDA A, 20

ADD A, 10

STO B, A

NOP Assembly Language

………………………………………………………………………………………..………………………

(d) On the Nairobi-Nakuru highway, the Kenya Police have put speed cameras at a certain point to read the time a vehicle passes a point (A) on the road and then reads the time it passes a second point (B) on the same road. (Points A and B are 200 meters apart). The speed of the vehicle is calculated using:

Speed = (Km/ hr)
The maximum allowed speed is 100 kilometers per hour.
500 vehicles were monitored using these cameras over a 1-hour period.

Write a pseudo code, which: (5 marks)
Inputs the start time and the end time for the 500 vehicles that were monitored
Calculates the speed for each vehicle using the formula above.
Outputs the speed for each vehicle and a message if the speed exceeded 100 km/hour.

>=100km/hr “High Speed”

<100km/hr “Normal Speed”

Start

starttime=0

Endtime=0

Speed=0

For Vehicles=1 To 500 Do

Input Start Time

Input Stop Time

Speed =100/(End Time-Start Time)

Print Speed

If Speed >100 Then

Print Over Speeding

Else

Print Normal Speed

ENDIF

NEXT VEHICLE

ENDFOR

STOP

Draw a flow chart for the above pseudo code. (5 marks)

MOKASA JOINT EXAMINATION

Kenya Certificate of Secondary Education

(a) In order to generate information from data items, a set of processing activities have to be performed on the data items in a specific sequence depending on the desired result.Draw a well labeled diagram to illustrate data processing cycle. (2 marks)

(b) A data entry clerk experiences some common errors when typing. Most of the time, she finds that:

After every calculation, the result is less than the expected number of digits required e.g.345.7896543 the result is given as 345.789.
Different charactersare typed wrongly, for example instead of typing12873457 she types 128734S7.

Identify the two types of errors commonly experienced by the clerk during data processing in (i) and (ii) above respectively. (2 marks)

Truncation error
Misreading error

Using modern data capture devices (direct data capture) such as barcode readers, optical character readers, digital cameras etc., which capture/enter data with minimum user involvement.
Design user interfaces that minimizes chances of invalid data entry.
Double entry checks
Use of error detection and correction software when transmitting and processingdata.
Use of automated data verification and validation routines in the data processing system.

(d)(i) State three advantages of a computerized filing system as used in data processing. (3 marks)

information takes up much less space than the manual filing
it is much easier to update or modify information
it offers faster access and retrieval of data
It enhances data integrity and reduces duplication
It enhances security of data if proper care is taken to secure it.

(ii) State two disadvantages of a serial file organization method in computing. (2 marks)

Itis cumbersome to access because you have to access all proceeding records before retrieving the one being searched.
Wastage of space on medium in form due inter-record gaps in storage.
It cannot support modern high speed requirements for quick record access.

(iii) Differentiate between distributed processing and interactive processing modes; stating one application area of each. (4 marks)

Distributed:

Various geographically dispersed computers arelinked by communication lines and all the computers linked belong to the same organization.
The computers are located at various departments or business sites for the individual departments or the business site to be served individually by its own computer resources.
All the branches have intelligent terminals (usually micro computers) linked to a big computer at the head office. Data from the branches is sent to the master where it is processed.

Interactive:

Occurs if the computer & the terminal user can communicate with each other.
It allows a 2-way communication between the user & the computer.
As the program executes, it keeps on prompting the user to provide input or respond to prompts displayed on the screen.
The user makes the requests and the computer gives the responses.
The data is processed individually and continuously, as transactions take place and output is generated instantly according totherequest made by user.

(a) Write the following acronyms in full as used in operating systems.

GUI – Graphical User Interface (½ mark)
WIMP – Windows, Icons, Menus and Pointers/ pointing devices. (½ mark)

(b) State three factors considered when choosing an operating system for use in a computer. (3 marks)

The hardware configuration of the computer e.g. Memory Capacity, processor speed & hard disk capacity.
The application software intended for the computer.
The user friendliness
The documentation available
The cost of the operating system.
Reliability and security provided by the operating system.
The number of processors & hardware it can support.
The number of users it can support.
The type of computers in terms of size and make. For example some earlier Apple computers would not run Microsoft Operating System.

File, Folder and Drive. State the meaning of theunderlined items respectively. (3 marks)

Files

A file is a collection of related data given a unique name for ease of access, manipulation and storage on a backing storage.

Folder

A named storage location where files are stored.
A container of files.
Also referred to as directories – Directories originate form a special directory called the root directory or folder.

Drives

A driveis a medium that is capable of storing and reading information that is not easily removed like a disk.

(d)(i) Differentiate between error handling and interrupt handling as used in operating systems.

(2 marks)

Error handling .

The OS has many ways of reporting to the user of any errors that occur during program execution. It does this by monitoring the status of the computer system & performing error checks on both hardware and software.
When the user makes an error, the OS through the Kernel determines the cause of the error, and prints diagnostic messages on the screen suggesting appropriate routines of how the error can be corrected.
In case of a fatal error that cannot be corrected, the program will be suspended permanently. g., the user program will prematurely terminate when it encounters an illegal operation, such as, dividing a no. by 0 or if it attempts to read a data file that had not been opened.

Interrupt handling

An Interrupt is a break from the normal sequential processing of instructions in a program.

Each hardware device communicates to the processor using a special number called the Interrupt Request number (IRQ). Therefore, when an interrupt occurs, control is passed to the Kernel, which determines the cause of the interrupt. The processor stops executing the current program to wait for the corrective response of the user. Control is returned to the program that was interrupted once corrective action has been taken.

(ii) State three reasons why most network technicians prefer using command line operating systems to configure networking equipment. (3 marks)

A CLIcan be a lot faster and efficient than any other type of interface.
It is secure since the expert only knows the commands.
A CLIrequires less memory to use in comparison to other interfaces.
A CLIdoesn’t require high graphics, hence a low-resolution monitor can be used.
A CLI does not require Windows to run

(e)Disk management is one important aspect insecondary storage in computer systems. Explain the following tools used by an operating system to manage disks in the computer. (3 marks)

Formatting
Writing electronic information (tracks and sectots) on the disk so that the computer can recognise the disk as a valid storagedevice and data can be stored.
The formatting process sets up a method of assigning addresses to the different areas. It also sets up an area for keeping the list of addresses. Without formatting there would be no way to know what data is where.
Partitioning
The act or practice of dividing the storage space of a hard disk drive into separate data areas known as partitions.
Defragmentation

Sometimes called defragging or disk optimisation is a software-controlled operation that reduces the amount of fragmentation in file systems by moving the scattered parts of files so that they once again are contiguous (attached).
the OS does this by physically organising the contents of the disk to store the pieces of each file close together and contiguously (elements of memory are said to be contiguous if they are adjacent to one another and appear to beconnected).

(a) Define the following terms as used in networking. (3marks)

Network
A collection 2 or more computers connected together using transmission media (e.g., telephone cables, or Satellites) for the purpose of communication and sharing of resources.
Intranet
Internal corporate network that uses the infrastructure of the Internet and the World Wide Web.
Browser
A browser (short for web browser) is a computer program/software that accesses webpages and displays them on the computer screen. It is the basic software that is needed to find,retrieve, view and send information over the internet.

(b) The World Health Organization is global entity that deals with health issues around the world. It has computer networks linking its regional and continental offices using internet. State two importance of the internet to such organization. (2 marks)

Communication with other organizations, with your members, with your staff, with your supporters and donors through e-mails, messenger, web pages, mail lists, web site message boards. The Internet greatly offers rapid communication on a global scale. It even delivers an integrated multimedia entertainment that any other mass medium cannot offer.
Publishing your message to the world using online books, journals, press releases, workshops, conferences, lectures. Websites with conference proceedings, PDF (Portable Document Format) files of your publications, blogs, newsfeeds e.t.c. support publishing.
Customer support – the people you are helping through your organization. It can help them when you aren’t there: email, messenger, web pages, mail lists, and web site message boards. With video-conferencing, podcasting and other great web tools, you can even have workshopsand classes online.
Research on news, issues, papers and literature relevant to your cause. Use of search engines tofind materials world-wide, mail lists e.t.c.
Leisure activities – e.g. online games, videos or music.
A place to do business and many other commercial activities. E.g. e-bay, amazon.com,e.t.c.

(c) Mr. Zuma, the Principal of a school wishes his school to have an internet connection in a bid to improve its service delivery. Mention fourinternet connectivity requirements that must be presentto enable the connection. (2 marks)

Transmission/Telecommunication/Network media
Data Terminal Equipments – A TCP/IP enabled computer with a web browser.
An account with an Internet Service Provider (ISP).
Networking equipment such as a modem, router or switch to connect the computer transmission media.

Inbox: Stores incoming mails (1 mark)
Drafts: Stores a saved copy of e-mails (usually composed but unsent) for later use. (1 mark)

(e) (i) Failure of information systems is a major concern in the security of data in computing systems. State twocauses of such failure. (2 marks)

Hardware failure due to improper use.
Unstable power supply as a result of brownout or blackout and vandalism.
Network breakdown
Natural disaster
Program failure/crash

(ii) Explain the following computer crimes.

Fraud (1 mark)
Fraud is the use of computers to conceal information or cheat other people with the intention of gaining money or information.
Industrial espionage (1 mark)
Involves spying on a competitor to get or steal information that can be used to finish the competitor or for commercial gain.The main aim of espionage is to get ideas on how to counter by developing similar approach or sabotage.

(f) Excluding passwords, state two other security control measures used to guard against unauthorized access to computers in a network. (2 marks)

Audit trails
Firewalls
Proxy servers
Log files/security monitors
Encryption
User access levels/Multilevel access
Biometric security
(a) Convert the 1010.011₂to decimal equivalent. ( 3 marks)

2³	2²	2¹	2⁰		2^-1	2^-2	2^-3
1	0	1	0	.	0	1	1
8	0	2	0		0.5	0.25	0.125

8+0+2+0 0+0.25+0.125 Ans = 10.375₁₀

(b) Perform the following number system conversions. (3 marks)

(i) 342.25₈tobinary.

3	4	2	.	2	5
011	100	010		010	101
011100010			.	010	101

Ans = 11100010.010101₂

(ii) 503₁₀ to hexadecimal (3 marks)

	Divide	Result	INT	DEC PART *16	Hex
Ignore decimal parts	503/16	31.4375	31	0.4375 X16 =7	7=7
	31/7	1.9375	1	0.9375 X 16 =15	15=F
	1/16	0.0625	0	0.0625 X 16 =1	1=1

Ans = 1F7

10111 + 10001 + 101

Carry digit ˃		1	1	1	1	1	1,1
	1	0	0	0	0	0	0
–					1	0	1
		1	1	1	0	1	1

Ans = 111011

(ii) Using 8-bit notation, perform the twos complementof 25₁₀ -15₁₀, leaving your answer in binary. (4 marks)

25 = 00011001

15 = 00001111

Ones complement/Bitwise NOT 15 = 11110000

Twos complement 15(11110000 + 1) = 11110001

Add the binary of 25 to the twos complement of 15 i.e. 00011001 + 11110001

Carry digit ˃	1	1	1				1
	0	0	0	1	1	0	0	1
	1	1	1	1	0	0	0	1
	(1)0	0	0	0	1	0	1	0

Ignore overflow bit. Ans = 00001010

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______________________________

MOKASA JOINT EXAMINATION

Kenya Certificate of Secondary Education

451/1 – COMPUTER STUDIES – Paper 1

2½hrs

Name……………………………………………………… Index Number……………………

Admission Number………….………………………………Class…………………………..

Date………………….……………..………

Instruction to candidates

Write your name and index number in the space provided above.
Sign and write the date of examination in the spaces provided above.
This paper consists of two sections A and B.
Answer all the questions in section
Answer question 16 and any other three questions from section
All answers should be written in the space provided in the question paper.
This paper consists of 14 printed pages.
Do not remove and pages from this booklet.
Candidates should check the question paper to ascertain that all the pages are printed as indicated and that no questions are missing.
Candidates should answer the questions in English.

For Examiner’s Use Only

Section	Question Number	Candidate’s Score
A	1-15
B	16
	17
	18
	19
	20
Total Score

SECTION A (40 MARKS)

ANSWER ALL QUESTIONS IN THIS SECTION

Name the two common types of system units and differentiate them. (2 marks)

………………………………………………………………………………………………….………….

Define the following characteristics of a computer system. (2 marks)

Versatile
Reliable

………………………………………………………………………………………………….………….………………………………………………………………………………………………….………….

………………………………………………………………………………………………….………….

Digital computers work with digital content. Describe a digital device. (2 marks)

………………………………………………………………………………………………….………….

Differentiate between third and fourth generation computers (2marks)

………………………………………………………………………………………………….………….

(a) Mamboleo company is in the process of computerizing its services. List four measures that should be put into consideration to protect the users in their computerized areas. (2marks)

………………………………………………………………………………………………….………….

Give two reasons why powder and liquid extinguishers are not recommended unlike gaseous extinguishers. (2marks)

………………………………………………………………………………………………….………….

Without proper marketing, a business cannot survive in a competitive environment hence computers are being used in a number of ways to enhance marketing. List any three ways of ensuring this is effected. (3 marks)

………………………………………………………………………………………………….………….

Differentiate between the following as used in computers. (3 marks)

Tab Key
Spacebar
Clicking

………………………………………………………………………………………………….………….

Control unit is an essential component of the CPU. Describe the functions of the control unit. (2 marks)

………………………………………………………………………………………………….………….

(a)Differentiate between buffers and Registers (2 marks)

………………………………………………………………………………………………….………….

(b)Speech recognition devices are used to capture natural sound and convert the input into digital form. State two problems related to speech recognition devices. (2 marks)

………………………………………………………………………………………………….………….

Define Solid-state storage and give two examples. (2 marks)

………………………………………………………………………………………………….………….

(a) Explain how a pixel affects the resolution of a monitor. (1 mark)

………………………………………………………………………………………………….………….

(b) List two types of computer output on microform (COM). (2marks)

………………………………………………………………………………………………….………….

Differentiate between high definition multimedia interface and Firewire (2 marks)

………………………………………………………………………………………………….………….

A warranty is an agreement between the buyer and the seller. It spells out terms and conditions after selling a product in case of failure or malfunction. Describe any three basic requirements a good warranty should cover. (3 marks)

………………………………………………………………………………………………….………….

(a)Differentiate between pasteboard and master page as used in DTP (2 marks)

………………………………………………………………………………………………….………….

Differentiate between graphic-based and layout based desktop publishing software. (2 marks)

………………………………………………………………………………………………….………….

Differentiate between Network database and Relational database. (2 marks)

………………………………………………………………………………………………….………….

SECTION B (60 MARKS)

ANSWER QUESTION 16 AND ANY OTHER THREE QUESTIONS IN THIS SECTION

(a) Define the following terms as used in programming (2 marks)
i) Source code

………………………………………………………………………………………..………………………

ii) Object code

………………………………………………………………………………………..………………………………………………………………………………………………………………..………………………

………………………………………………………………………………………..………………………

(b) Differentiate between Assembler and Interpreter as used in programming. (2 marks)

………………………………………………………………………………………..………………………

(i) 1101 1101 1011 1011

1110 0001 1100 0111

0010 1110 1011 0011

………………………………………………………………………………………..………………………

(ii) LDA A, 20

ADD A, 10

STO B, A

NOP

………………………………………………………………………………………..………………………

Speed = (Km/ hr)
The maximum allowed speed is 100 kilometers per hour.
500 vehicles were monitored using these cameras over a 1-hour period.

Write a pseudo code, which: (5 marks)
Inputs the start time and the end time for the 500 vehicles that were monitored
Calculatesthe speed for each vehicle using the formula above.
Outputs the speed for each vehicle and a message if the speed exceeded 100 km/hour.

>=100km/hr “High Speed”

<100km/hr “Normal Speed”

Draw a flow chart for the above pseudo code. (5 marks)

(a) In order to generate information from data items, a set of processing activities have to be performed on the data items in a specific sequence depending on the desired result.Draw a well labeled diagram to illustrate data processing cycle. (2 marks)

(b) A data entry clerk experiences some common errors when typing. Most of the time, she finds that:

After every calculation, the result is less than the expected number of digits required e.g.345.7896543 the result is given as 345.789.
Different charactersare typed wrongly, for example instead of typing12873457 she types 128734S7.

Identify the two types of errors commonly experienced by the clerk during data processing in (i) and (ii) above respectively. (2 marks)

…………………………………………………………………………………………………………………

(d)(i) State three advantages of a computerized filing system as used in data processing. (3 marks)

…………………………………………………………………………………………………………………

(ii) State two disadvantages of a serial file organization method in computing.

(2 marks)

…………………………………………………………………………………………………………………

(iii) Differentiate between distributed processing and interactive processing modes; stating one application area of each. (4 marks)

…………………………………………………………………………………………………………………

(a) Write the following acronyms in full as used in operating systems.

GUI (½ mark)

………………………………………………………………………………………..………………………

WIMP (½ mark)

………………………………………………………………………………………..………………………

(b) State three factors considered when choosing an operating system for use in a computer. (3 marks)

………………………………………………………………………………………..………………………

File, Folder and Drive. State the meaning of theunderlined items respectively. (3 marks)

………………………………………………………………………………………..………………………

(d)(i) Differentiate between error handling and interrupt handling as used in operating systems.

(2 marks)

………………………………………………………………………………………..………………………

(ii) State three reasons why most network technicians prefer using command line operating systems to configure networking equipment. (3 marks)

………………………………………………………………………………………..………………………

(e)Disk management is one important aspect insecondary storage in computer systems. Explain the following tools used by an operating system to manage disks in the computer. (3 marks)

Formatting

………………………………………………………………………………………..………………………

Partitioning

………………………………………………………………………………………..………………………

Defragmentation

………………………………………………………………………………………..………………………

(a) Define the following terms as used in networking. (3marks)

Network

………………………………………………………………………………………..………………………

Intranet

………………………………………………………………………………………..………………………

Browser

………………………………………………………………………………………..………………………

Inbox (1 mark)

………………………………………………………………………………………..………………………

Drafts (1 mark)

………………………………………………………………………………………..………………………

(e) (i) Failure of information systems is a major concern in the security of data in computing systems. State twocauses of such failure. (2 marks)

………………………………………………………………………………………..………………………

(ii) Explain the following computer crimes.

Fraud (1 mark)

………………………………………………………………………………………..………………………

Industrial espionage (1 mark)

………………………………………………………………………………………..………………………

(f) Excluding passwords, state two other security control measures used to guard against unauthorized access to computers in a network. (2 marks)

………………………………………………………………………………………..………………………

(a) Convert the 1010.011₂ to decimal equivalent. ( 3 marks)

………………………………………………………………………………………..………………………

(b) Perform the following number system conversions. (3 marks)

(i) 342.25₈tobinary.

………………………………………………………………………………………..………………………

(ii) 503₁₀ to hexadecimal (3 marks)

………………………………………………………………………………………..………………………

10111 + 10001 + 101

………………………………………………………………………………………..………………………

(ii) Using 8-bit notation, perform the twos complementof 25₁₀ -15₁₀, leaving your answer in binary. (4 marks)

………………………………………………………………………………………..………………………

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QN	Section/Activity		Marks	Max mark	Marks awarded
1.	a)	Creating workbook MASL REPS – Naming Worksheet 1 As Sales – Typing data accordingly,into rows/columns – Input validation, with correct parameters	1 mark 1 mark 18 marks 3 marks	23 marks
	b)	Using correctformulae to: (i) Total Sales for each sales rep (ii) Total Sales for each product	2 marks 2 marks	4 marks
	c)	Inserting Bonus Points column& Computing points – Create column – Using appropriate function or formulae Calculate/compute bonus	1 mark 1 mark 2 marks	4 marks
	d)	Inserting column Awards – Use of IF function to display remarks	1 mark 4 marks	5 marks
	e)	Formatting worksheet – Double underline – Font type – Algerian – Font size – 26pts – Applying borders to data in worksheet	1 mark 1mark 1 mark 1 mark	4 marks
	f)	Rotating headings: All Product Type heading labels(Sales Rep., Faiba, Gateway, Vodafone, SAF, Total Sales).	1mark	1 mark
	g)	Inserting chart: Total sales vs Sales representatives – Chart title – X axis title – Y axes title – Legend – Data labels (Minimum & maximum ranges) Renaming worksheet 2 as CHART	1 mark 1mark 1 mark 1 mark 1 mark 1 mark 1 mark	7 marks
	h)	Printing worksheets: – MASL – CHART	1 mark 1 mark	2 marks
		TOTAL MARKS	50 MARKS

Qestion 2 -Word Processing
No.		Particulars	Marks	Award
a.		fully typed text	5
		4 Paragraphs indication @ 1/2 Mark each	2
		dropcap	1
		columns	1
		Bullets	1
		line between columns	1
		paragraph title italics & bolding	2
		Correctly filled table	3
		table correct outer border	1
		table row shading and text color( white)	1
		correctly drawn diagram	3
		saving with correct file name	1
b		creating a copy	1
b		saving with correct file name	1
c		heading format @ 1/2 Mark each	3
d		correct header	1
d		correct footer	1
e		spelling error free	2
f		correct alignment	1
g		finding and replacing all	1
h		resizing diagram	1
		object placement	1
		text readability over graphics	1
j	i	cell splitting	1
	ii	inserting row	1
		cell merging	1
		appropriate row heading	1
k	i	total score	2
	ii	number of students	2
	iii	highest score	2
	iv	average total score	2
l	i	print EDUC AI	1
l	ii	print EDUC AI2	1
TOTAL MARKS			50

___________________________________________

451/2 COMPUTER STUDIES- PAPER 2

(PRACTICAL)

2 ½ hours

MOKASA 1 JOINT EXAMINATION

Kenya Certificate of Secondary Education

(K.C.S.E)

Instructions to candidates

Indicate your name and index number at the top right hand corner of each printout
Write your name and index number on the CD/Removable storage medium provided.
Answer all the questions
All questions carry equal marks
Passwords should to be used while saving in the CD/Removable storage medium
All answers must be saved in your CD/Removable storage medium
Make a printout of the answers on the answer sheet
Arrange your printouts and tie/staple them together
Hand in all the printouts and the CD/Removable storage medium used
This paper consist of 5 printed pages
Candidates should check the question paper to ascertain that all the pages are printed as indicated and that o questions are missing

MASL is a company thatengages in the sales of the following Mobile service providers: Faiba, Gateway, vodafone and SAF. The company uses sales representatives who operate at various regions in Nakuru town. Each sales representative presents monthly sales to the manager (Values are in Ksh).

	A	B	C		D	E	F
1	Mobile_Accessories Sales LTD
2		Product type
3	Sales Rep.	Faiba		Gateway	Vodafone	SAF	Total Sales
4	Kipkulei	24000		37500	39500	49500
5	Tom	15000		26500	21500	25500
6	Sharon	5500		14800	3500	16500
7	Oscar	7000		15500	14500	64500
8	Linda	11000		69000	2200	64500
9	Danelaw	33500		12000	14500	25500
10	Muriithi	15500		80000	17200	23500

Using spreadsheet package,
Enter the information given in the table 1 into a worksheet.Save workbook as MASLREPSand rename sheet 1 as (20 marks)
Validate all the cells in the Product Type columns to allow entry of numeric data only.

A message, “Invalid data! Enter numbers” should be displayed whenever a cell is typed with non-numeric data. (3 marks)

Using formulae, determine the;
Total sales for each Sales representative (2 marks)
Producttype Total Sales for each month. (2 marks)
Each sales person earns Bonus points for the sales of each product type based on the following criteria.
1 point if sales are greater than 50,000 for Faiba,
2 points if sales are greater than 60,000 Gateway,
3 points if sales are greater than 50,000 Vodafone
2 points if sales are greater than 60,000 for SAF

Insert a column BonusPoints and compute the points of each sales Person. (4 marks)

Insert a blank column Awardsand based on the TotalSales earned by each sales representative. Use a function to display the remarks on Awards as follows: (5 marks)

Total Sales Awards

More than 250,000 Cash

More than 100, 000 and less than 250,000 Voucher

Less than 100,000 Try again

Format the figures in worksheet as follows: (4 marks)
Title and subtitle:
Double underline
Font type – Algerian
Font size 26
Apply borders to the data in the workbook.

Rotate Up, all the Product Type heading labels in the worksheet. (1 mark)
Generate a column chart to representthe Total sales for each salesrepresentative. Label your chart accordingly and place it in worksheet 2 renamed as CHART. (7 marks)
Print MASL and CHART (2 marks)

Using word processing program type the document as it appears and save it asEDUC AI

ARTIFICIAL INTELLIGENCE IN EDUCATION

For decades, science fiction authors, futurists, and movie makers alike have been predicting the amazing (and sometimes catastrophic) changes that will arise with the advent of widespread artificial intelligence. So far, AI hasn’t made any such crazy waves, and in many ways has quietly become ubiquitous in numerous aspects of our daily lives. From the intelligent sensors that help us take perfect pictures, to the automatic parking features in cars, to the sometimes frustrating personal assistants in smartphones, artificial intelligence of one kind of another is all around us, all the time.

hile we may not see humanoid robots acting as teachers within the next decade, there are many projects already in the works that use computer intelligence to help students and teachers get more out of the educational experience. Here are just a few of the ways those tools, and those that will follow them, will shape and define the educational experience of the future.

Automation of basic activities in education, like grading.
Educational software can be adapted to student needs.
It can point out places where courses need to improve.
Students could get additional support from AI tutors.
AI may change where students learn and how they acquire basic skills.
It is altering how we find and interact with information.

Automation basic activities in education, like grading.
In lower grades, teachers often find that grading takes up a significant amount of time, time that could be used to interact with students, prepare for class, or work on professional development.A1 can be used to automate grading systems and present the output in tables .

GRADE THREE COMMON EXAMINATION
SIR NAME	LANGUAGE SKILLS	COMPUTING SKILLS	ENVIRONMENTAL SKILLS	*Total Score*
Macmillan	87	50	78
Trevor	92	95	76
Johnstone	73	85	90
Kathleen	67	56	75
*Count*
*Highest Scores*

Educational software can be adapted to student needs.

From kindergarten to graduate school, one of the key ways artificial intelligence will impact education is through the use of application programs.learners can draw 3D diagramssuch as the one shown below

Teachers may not always be aware of gaps in their lectures and educational materials that can leave students confused about certain concepts. Artificial intelligence offers a way to solve that problem.

using a word processing application software type the document below as it appears and save it as EDUC AI (22 Marks)
Copy the document EDUC AI in a new document and save it as EDUC AI2 then use it to answer the questions that follows (2 Marks)
Format the heading as follows;

Center align, font size – 14, font color – red, font type – Algerian, double underline, scale – 130% (3 Marks)

Insert your name, Adm No ,system time as a header and your class and page number as a footer (2 Marks)
Spell check the document to remove all typing errors (2 Marks)
Center align the first paragraph (1 Mark)
Find all occurrences of the word AI in the document and replace with “Artificial Intelligence “ (1 Mark)
Resize the diagram between the last two paragraphs and move it to the second paragraph and send it behind text (3 Marks)
On the grade three table,

Split the cells in the total score column to separate each students’ marks (1 Mark)
Insert a new row at the bottom of the table to display the average total scores and merge the first four columns of the row (3 Marks)

Use appropriate function to calculate:

Total score (2 Marks)
Number of students who did each exam (2 Marks)

Highest score attained in each subject (2 Marks)

Average total scores (2 Marks)
PrintEDUC AI (1 Mark)
EDUC AI2 (1 Mark)