WAEC SSCE - Data Processing - 2019 (Essay and Test of Practical Work)

Answer Details

This scenario tests the reasons for networking computers and the devices needed to build a network.

(a) Four reasons that motivated connecting the computers.

• To share hardware resources such as printers and scanners among many users.
• To share files and data easily between the computers.
• To enable communication (for example messaging and email) between users.
• To allow centralised management, security and backup, and to share a single Internet connection (also reducing cost).

(b) Four network devices required. A switch (or hub), a router, a network interface card (NIC), and transmission cable such as UTP with connectors (a modem or wireless access point is also acceptable).

(c) One function each of any two of the devices.

• Switch: connects computers within the network and forwards data only to the specific computer it is addressed to.
• Router: connects the network to another network (such as the Internet) and directs data along the best path between networks.
• (NIC: gives a computer its network address and provides the physical connection to the network.)

Examination reminder: distinguish the two connecting devices - a switch links computers within one network, while a router links different networks together.

Answer Details

This question tests teleconferencing, ATM uses, the modem and transmission means.

(a) Teleconferencing. Teleconferencing is the use of telecommunication and computer technology to hold a meeting or conversation between two or more people in different locations at the same time, using audio and/or video links so they can see and/or hear one another.

(b) Four uses of the Automated Teller Machine (ATM).

• Withdrawing cash.
• Checking account balance.
• Transferring funds between accounts.
• Paying bills / buying airtime (also PIN change and mini statement).

(c)(i) Function of a modem. A modem (modulator-demodulator) converts the computer's digital signals into analog signals for transmission over a communication line (modulation) and converts incoming analog signals back into digital form (demodulation), so that computers can communicate over telephone or similar lines.

(c)(ii) Two means of transmitting information. Through guided/wired media such as cable (twisted-pair, coaxial or fibre-optic) and through unguided/wireless media such as radio waves, microwaves or satellite.

Examination reminder: remember the modem does two opposite jobs - modulation (digital to analog) when sending and demodulation (analog to digital) when receiving.

Answer Details

This question tests the application of ICT in different professions. For each friend, state two realistic ICT applications in that specific job.

• Hamza (pilot): uses ICT for computerised flight-navigation and autopilot systems, and for flight simulators used in training; also for radio/radar communication with air-traffic control.
• Emeka (businessman): uses ICT for e-commerce (online buying and selling) and for keeping accounts and records with spreadsheets and databases; also for e-mail and online marketing.
• Funsho (banker): uses ICT for electronic banking such as ATMs and online transfers, and for maintaining customer accounts on a database; also for processing transactions securely.
• Fejiro (manufacturer): uses ICT for computer-controlled/automated production machinery (CAM and robotics) and for computer-aided design (CAD) of products; also for inventory and production control.
• Idongesit (teacher): uses ICT for e-learning and preparing lessons/presentations, and for computer-based setting, marking and record-keeping of results; also for online research.

Examination reminder: tie each ICT use to the actual duties of the profession named; a general answer such as "sends email" earns less than a job-specific one such as "a pilot uses computerised navigation systems".

Answer Details

This question tests core database-modelling terms and cardinality.

(a) Database-management terms.

• (i) Entity: a real-world object, person, place, event or concept about which data is stored in a database (for example a Student, a Book or a Customer). Each entity becomes a table.
• (ii) Attribute: a property or characteristic that describes an entity (for example a Student's name, registration number or date of birth). Attributes form the columns/fields of the table.
• (iii) Relationship: a meaningful association or link between two or more entities (for example a Student "borrows" a Book), showing how their records are connected.

(b)(i) Cardinality. Cardinality describes the number of instances of one entity that can be associated with instances of another entity in a relationship, that is the degree of the relationship between two tables.

(b)(ii) Three cardinality relationships.

• One-to-one (1:1): one record in the first entity relates to exactly one record in the second.
• One-to-many (1:M): one record in the first entity relates to many records in the second.
• Many-to-many (M:N): many records in the first entity relate to many records in the second.

Examination reminder: keep the three terms in order - an entity is the thing, an attribute describes it, and a relationship links entities; cardinality then counts how many on each side (1:1, 1:M, M:N).