Computer studies analysis of questions and answers

Explain three functions of an information system in an organisation.

15/1/2021

Explain three functions of an information system in an organisation.

(b) Explain two benefits that a company would gain from using batch processing method for data processing

(c) (i) Convert the number 11101.1 1₂ to its decimal equivalent.
(ii) Perform the following binary operation 11011₂ + 101₂

RESPONSES

a) Functions of information system in an organization.

Process data in an organization according to the policies and objectives.
Decision making by providing information that helps with strategic planning within the organization.
Means of communication and flow of information to various sections of an organization / enable sharing of information.
Improving quality of production, through the use of feedback mechanisms for counter checking the production with expected results.

(b)Benefits of using batch processing.

Output is increased because the processor work is uninterrupted.
Low cost of operation since the tasks are processed as a group.
Requires little supervision since the processing runs automatically as long as the instructions is given.
Less labour required since the process is automatic.
Efficient use of computer resources due to no idle time.
Gives company opportunity to check any error before processing begins.

(c) (i) Convert the number 11101.1 12 to its decimal equivalent. (ii) Perform the following binary operation 110112 + 1012

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A school has been advised to employ a database administrator. State three responsibilities of this personnel in the school.

15/1/2021

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A school has been advised to employ a database administrator. State three responsibilities of this personnel in the school.

(b) Explain two ways in which computers can be used in the transport industry.
(c) Mary was advised to partition a hard disk for her computer. Explain two reasons that may have necessitated this.
(d) Explain a reason for conducting each of the following studies in systems development:
(i) Schedule feasibility;
(ii) Technical feasibility.

RESPONSES

a) Possible responsibilities of a database admin in a school

Carrying out school database backups.
Recovering of lost school data incase of system failure.
Ensuring the security and integrity of the school system.
Adding new users to the school system and managing the user’s accounts.
Designing and developing database application for the school.
Updating or maintaining database for the school.

b) Ways in which computers can be used in a transport industry.

Use of GPS to track vehicles, flights etc.
Bookings to different destinations can be done through the use of computers ( online booking).
The computers can also be used to reduce the speed of vehicles and bring sanity in the industry.
Managing human resource involved in the industry.

c) Reasons for partitioning hard disk

For security purposes, incase one partition fails the second partition remains functional.
If she requires backup copies to be stored in the same hard disk.
If she intends to install more than one operating system.

d) (I Schedule feasibility

To determine if the proposed solution can be developed within the required time.

(ii) Technical feasibility

To determine if the system can be supported by the available technology.

(b) Explain two ways in which computers can be used in the transport industry. (c) Mary was advised to partition a hard disk for her computer. Explain two reasons that may have necessitated this. (d) Explain a reason for conducting each of the following studies in systems development: (i) Schedule feasibility; (ii) Technical feasibility.

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Describe three arithmetic errors that may occur during computerised data processing.

15/1/2021

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Describe three arithmetic errors that may occur during computerised data processing.

(b) Arnold a programmer intends to create a user input interface screen for a system. State three factors that he should consider.
(c)With the aid of an example in each case describe the following types of maintenance.
(i) adaptive;
(ii) perfective;
(iii) corrective.

RESPONSES

a) Arithmetic errors
Truncation error

Results due, to shortening or leaving out part of a number or a word.
Rounding off error
Arising by approximating a number by replacing it with a number that has fewer significant digits or one with zeros for its ending digits.

Overflow error

Occurs when the results of a computation is larger than the allocated memory space.

Underflow error

Type of error occurs when the output is low small to be represented in the chosen format.

b) User interface design considerations

Should be user friendly.
Colour, fonts and layout should be appealing to the user.
Consider a consistent layout in the entire system.
Should prompt user clearly.
Should capture the same number of items of date as indicated in the manual data capture form.

(c)Types of maintenance
(i) Adaptive

Type of maintenance that is done to make the system to adopt the changing technology e.g. changing the system because to new ois

(ii) Perfective

Type of maintenance done to make the system better in its operation e.g. adding a module in a system.

(iii) Corrective

Type of maintenance done to correct an error in the system e.g.wrong results during addition.

a) Arithmetic errors Truncation error Results due, to shortening or leaving out part of a number or a word. Rounding off error Arising by approximating a number by replacing it with a number that has fewer significant digits or one with zeros for its ending digits. Overflow error Occurs when the results of a computation is larger than the allocated memory space. Underflow error Type of error occurs when the output is low small to be represented in the chosen format. b) User interface design considerations Should be user friendly. Colour, fonts and layout should be appealing to the user. Consider a consistent layout in the entire system. Should prompt user clearly. Should capture the same number of items of date as indicated in the manual data capture form. (c)Types of maintenance (i) Adaptive Type of maintenance that is done to make the system to adopt the changing technology e.g. changing the system because to new ois (ii) Perfective Type of maintenance done to make the system better in its operation e.g. adding a module in a system. (iii) Corrective Type of maintenance done to correct an error in the system e.g.wrong results during addition.

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State two qualities of a good pseudocode.

15/1/2021

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State two qualities of a good pseudocode.

should be short and clean precise
should have start and end clearly shown.
Statements should be clearly defined.
should depict the logical flow of solving the problem.
should not be ambiguous.
it should be indented /neat / legibility

(b) With the aid of flowchart diagrams, describe each of the following programme control structures:
(i) sequence
(ii) selection

(i)Sequence

Program statements are executed one after the other in the order in which they appear.

(ii) Selection

(c) Draw a programme flowchart that would accept three numbers and find their sum. If the sum is greater than 200. It adds 30 to the sum, otherwise subtracts 20 from the sum. The programme should then display the results.

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Explain two health issues that could arise from the use of unsuitable computer desk.

13/1/2021

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Explain two health issues that could arise from the use of unsuitable computer desk.

It could lead to back problems if the desk is of an unrealistic height.
If it does not provide good positioning of the monitor, it could result in eye strain.
Wrist problems will arise if the keyboard and mouse seating positions are bad.
Injury as a result of falling computer components due to weak computer desks/ small size.

(b i)Describe two ways in which a positive number and a negative number can be represented in a computer

In binary one bit usually the most significant or leading bit is used to indicate either positive or negative,and store the unsigned binary representation of the magnitude in the remaining bits.
Signed magnitude.
Using the twos complement.
Using the ones complement.

(ii) A particular computer stores numbers in a single 8-bit word.
Determine how the number 0.3125 base 10 would be represented.

No.18.(a) Explain two health issues that could arise from the use of unsuitable computer desk. It could lead to back problems if the desk is of an unrealistic height. If it does not provide good positioning of the monitor, it could result in eye strain

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Figure 1 shows a flowchart. Use it to answer the questions that follow.

13/1/2021

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Figure 1 shows a flowchart. Use it to answer the questions that follow.

(a) Interpret the flowchart.
(b) Write a pseudo code for the flowchart.

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A water company sends out clerks to read meters. The data collected by the clerks is then fed into the computer and then all bills are printed at the same time.

13/1/2021

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A water company sends out clerks to read meters. The data collected by the clerks is then fed into the computer and then all bills are printed at the same time.

(a)State two advantages of this approach;

Shifts time of processing to when computers are less busy.
No user input required hence no idle computer time as it awaits input.
Input is done once (batch).
Can enable use of hired equipment hence cost effective.

(b) Name this type of data processing.

Batch processing.
Electronic

A water company sends out clerks to read meters. The data collected by the clerks is then fed into the computer and then all bills are printed at the same time.

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An organisation intends to replace an existing system by carrying out the process in stages.

12/1/2021

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An organisation intends to replace an existing system by carrying out the process in stages.

(a) Name this implementation strategy;

The implementation strategy is: - phased change-over/modular

(b)Give two reasons why the organisation is opting to use the implementation strategy in (a) above.

It gives employees opportunity to learn
Organization can revert to old system in case of failure.
Reduces resistance by employees.

(c) A manager wishes to replace the current manual system with a computerised one. Describe three main areas that must be evaluated to justify the replacement.
Technical feasibility:

Does' the current technology (hardware & software) allow.

Economic feasibility:

Are funds available?

Social feasibility:

How will the new system impact on the organization/society?

An organisation intends to replace an existing system by carrying out the process in stages.

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Convert each of the following binary numbers to decimal equivalent given that the left most digit is a sign bit:

12/1/2021

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Convert each of the following binary numbers to decimal equivalent given that the left most digit is a sign bit:

(a) 00101101
(b) 11001001

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State two ways in which software errors can be prevented in program development.

12/1/2021

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State two ways in which software errors can be prevented in program development.

Use of anti-virus software.
Update system frequently.
Purchase software from authentic sources.
Test the software before implementation.
Test syntax/logic.
Proper training.
Proper enactment of laws.

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Convert the decimal number 20.373 to its binary number system equivalent

12/1/2021

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Convert the decimal number 20.373 to its binary number system equivalent. (3 marks)

Converting 20 base 10 into binary

since the result was long, we just decided to truncate at 16th digit however it can exceed

0.373₁₀ = 0101111101111100₂

The binary result of 20.373₁₀ is therefore

20₁₀ = 10100₂ and
0.373₁₀ = 0101111101111100₂

Combine them all;

20.373₁₀ = 10100.0101111101111100₂

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List two techniques of acquiring electronic images to be used in a desktop publishing program.

10/1/2021

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List two techniques of acquiring electronic images to be used in a desktop publishing program.

(ii) Describe two layout guides in a desktop publishing program (DTP) that assist a user to place an object in a preferred position.
(b) Explain three ways of ensuring that data submitted for processing is accurate.
(c)An engineering company requires a computer system to design roads and bridges.
Explain one suitable choice for:
(i) output device;
(ii) software.

RESPONSES

(a) (i) Ways of acquiring images in DTP:

Scanning;
Picture capture via camera;
downloading;
getting from secondary storage.

(ii) Layout guides

Ruler guides: a ruler on the edges of the page that guides a user to position objects and resize them;
Margin guides: used to define page margins so that the user will be prevented from placing objects in non-printable areas of the page;
Column guides: Vertical lines used to divide a page into two or more columns;
Row guides: Lines used to divide a publication page into two or more section to help structure the layout;
Snap points: Positions on the screen where the object is stuck on.

(b) Ways of ensuring accuracy of data during data processing

Data is stored in secondary storage in such a way that access to it is controlled.
Encrypting of data before it is transmitted to minimize chances of it being compromised during transmission.
Use of validation methods to ensure that data is correct at the point of input.
Use of direct data capture methods which eliminates human errors.
Use of verification methods.

(c) (i) Output device: A plotter because it prints large size drawings to high precision.
(ii) A CAD software because it facilitates in the design of engineering drawings.

(ii) Describe two layout guides in a desktop publishing program (DTP) that assist a user to place an object in a preferred position. (b) Explain three ways of ensuring that data submitted for processing is accurate. (c)An engineering company requires a computer system to design roads and bridges. Explain one suitable choice for: (i) output device; (ii) software.

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State three functions of networking operating systems other than providing network security.

10/1/2021

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State three functions of networking operating systems other than providing network security.

(b) Explain three ways in which an operating system provides data security in a computer system.
(c) Explain three circumstances under which observation method may be preferred during data collection.

(a) Functions of network operating systems

Provide access to network resources;
Supporting network services like protocols;
Support communication;
Respond to requests from applications;

(b) Ways in which an operating system provides data security

Access control: Deals with the problem of verifying /authenticating the identity of a user before permitting access to the request resource (e.g. use of passwords, user account);
Encryption - Transforming data into an unreadable format so that they are safely transmitted;
Firewalls - Filters out unwanted data and programs/criminals/hackers/malicious persons;
Log files - A means by which transactions in a computer system can be recorded thereby deterring potential infiltrators;
Alerts - Alerting a user when he/she is about to delete a file/folder.

(c)Preference of observation during data collection

When the subjects that are being observed need not be made aware of the fact;
When there is need to directly see what subjects do rather than rely on what they tell you;
When there is need to collect data without interfering with the working of the subjects;
When nature of data can only be collected via observation e.g. traffic flow;
When collecting data in situation that subjects may be unwilling to give information.

(b) Explain three ways in which an operating system provides data security in a computer system. (c) Explain three circumstances under which observation method may be preferred during data collection.

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In the BCD number coding scheme, letter A is represented by 110001 and letter B by 110010. Determine how the word CAB is coded in BCD.

10/1/2021

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In the BCD number coding scheme, letter A is represented by 110001 and letter B by 110010. Determine how the word CAB is coded in BCD.

(ii) Convert the decimal number 11.125 to its binary number system equivalent.
(iii) Perform the binary arithmetic: 111.01 + 1011.111 — 101.011 and convert the answer to decimal notation.
(b) Explain the importance of each of the following in word processing:
(i) tab stops;
(ii) section breaks.
(c) State three documents that are used during mail merging in word processing.

ANSWERS

(b) Importance of tab stops and section break

(i) Tab stop: when tab stops are set, they allow aligning of text into columns;
(ii) Section breaks: Allows splitting of a document into different sections so that different formatting styles can be applied to the different sections.

Main document - primary/secondary/data source
The address list - the intended recipients of the document.
The merged document - final document ready for printing or sending.

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List four web programming languages.

10/1/2021

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List four web programming languages.

HTML - Hyptertext Mark-up Language
Java script
VBScript - Visual Basic script
XML - Extensible Markup Language
PHP - Hypertext Preprocessor
SQL - Structured Query Language
Dream weaver
Front page

State four ways in which a programmer can make program code easy to fol1ow

Using modules or short blocks of program/functions/procedures;
Making internal documentation / comments;
Using meaningful variable names and user words in the program;
Using indent to represent nested statement:
Using blank lines to separate blocks of code statement;
Test formatting of reserved words e.g. bolding

Draw a program flowchart to represent the following pseudocode.

ANSWER

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ANALYSIS OF KCSE COMPUTER STUDIES TOPICAL QUESTIONS & REVISION KITS

Explain three functions of an information system in an organisation.

A school has been advised to employ a database administrator. State three responsibilities of this personnel in the school.

Describe three arithmetic errors that may occur during computerised data processing.

State two qualities of a good pseudocode.

(b) With the aid of flowchart diagrams, describe each of the following programme control structures: (i) sequence (ii) selection

​(c) Draw a programme flowchart that would accept three numbers and find their sum. If the sum is greater than 200. It adds 30 to the sum, otherwise subtracts 20 from the sum. The programme should then display the results.

Explain two health issues that could arise from the use of unsuitable computer desk.

Figure 1 shows a flowchart. Use it to answer the questions that follow.

A water company sends out clerks to read meters. The data collected by the clerks is then fed into the computer and then all bills are printed at the same time.

An organisation intends to replace an existing system by carrying out the process in stages.

Convert each of the following binary numbers to decimal equivalent given that the left most digit is a sign bit:

State two ways in which software errors can be prevented in program development.

​Convert the decimal number 20.373 to its binary number system equivalent. (3 marks)

0.37310 = 01011111011111002

The binary result of 20.37310 is therefore

2010 = 101002 and

0.37310 = 01011111011111002

20.37310 = 10100.01011111011111002

List two techniques of acquiring electronic images to be used in a desktop publishing program.

State three functions of networking operating systems other than providing network security.

In the BCD number coding scheme, letter A is represented by 110001 and letter B by 110010. Determine how the word CAB is coded in BCD.

List four web programming languages.

State four ways in which a programmer can make program code easy to fol1ow

​Draw a program flowchart to represent the following pseudocode.

Categories

Archives

(b) With the aid of flowchart diagrams, describe each of the following programme control structures:
(i) sequence
(ii) selection

(c) Draw a programme flowchart that would accept three numbers and find their sum. If the sum is greater than 200. It adds 30 to the sum, otherwise subtracts 20 from the sum. The programme should then display the results.

Convert the decimal number 20.373 to its binary number system equivalent. (3 marks)

0.373₁₀ = 0101111101111100₂

The binary result of 20.373₁₀ is therefore

20₁₀ = 10100₂ and

0.373₁₀ = 0101111101111100₂

20.373₁₀ = 10100.0101111101111100₂

Draw a program flowchart to represent the following pseudocode.