neco 2020 data_processing | Essay

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Question 1 View Details
A secondary school conducts a survey to find out the preferred mode of transport to school among its 200 students. The raw responses are recorded as follows: 80 students walk, 50 take a bus, 30 ride bicycles, 20 are driven by parents, and 20 use other means.
Question Parts
(a)
Define the terms **data** and **information** in the context of the above survey.
(b)
List the four stages of the data processing cycle and give a brief description of how each stage would be applied to this survey.
(c)
Calculate the percentage of students using each mode of transport and state which mode is the most popular.
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Question 2 View Details
The sales department of a small company recorded the number of units of Product X sold each month for the first half‑year of 2024. The unit sales are shown in the table below. The selling price per unit is ₦250. | Month | Units sold | |-------|------------| | Jan | 120 | | Feb | 150 | | Mar | 130 | | Apr | 160 | | May | 140 | | Jun | 180 | Using this information, answer the following questions.
Question Parts
(a)
Calculate the revenue earned in each month and the total revenue for the six‑month period.
(b)
Determine the following statistical measures for the unit‑sales data: (i) mean, (ii) median, (iii) mode (if any).
(c)
Construct a frequency distribution for the unit‑sales using the class intervals 100‑119, 120‑139, 140‑159, 160‑179, 180‑199. State which interval has the highest frequency.
(d)
Which type of graph – a bar chart or a line graph – would better represent the trend in monthly sales and why?
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Question 3 View Details
A small business uses a computer system to manage its inventory. The system receives daily sales data, updates stock levels, generates reorder reports and produces monthly sales summaries. The manager notices that the monthly summary sometimes shows a total that does not match the sum of the daily reports.
Question Parts
(a)
List and briefly describe the five stages of the data processing cycle as applied to this system.
(b)
Identify which stage(s) of the cycle are most likely responsible for the discrepancy and explain why.
(c)
Propose a systematic procedure, using the cycle, to locate and correct the error.
(d)
Discuss two advantages of using a well‑defined data processing cycle in such a business.
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Question 4 View Details
A secondary school computer lab maintains student records. Each record contains: admission number (8 digits), name (up to 30 characters), date of birth (DD/MM/YYYY), and three subject scores (each 0‑100). The lab administrator is considering two ways to store the records on a hard disk: (i) sequential file organization, (ii) indexed sequential access method (ISAM) with a primary index on admission number.
Question Parts
(a)
Define sequential file organization and indexed sequential file organization.
(b)
Calculate the minimum disk space required to store 500 student records using each method, assuming: each character occupies 1 byte, each numeric field occupies 4 bytes, and an index entry consists of the admission number (8 bytes) plus a 4‑byte pointer. Ignore block overhead.
(c)
Based on the calculations and typical operations (searching for a student, adding a new record, deleting a record), recommend which organization is more suitable and justify your recommendation.
(d)
Explain one potential drawback of the recommended method.
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Question 5 View Details
A small retail store maintains a database to record its sales transactions. The store has three entity types: **Product** (ProductID, Name, UnitPrice), **Customer** (CustomerID, Name, MembershipLevel), and **Sale** (SaleID, Date, CustomerID). Each sale may include multiple products; the quantity of each product sold is recorded in a junction entity **SaleItem** (SaleID, ProductID, Quantity). The attribute MembershipLevel can take the values 'Standard', 'Silver' or 'Gold'. The store offers a discount on the total amount of a sale based on MembershipLevel: Standard – no discount, Silver – 5 % discount, Gold – 10 % discount.
Question Parts
(a)
Draw a complete ER diagram for the described situation. State the entity sets, attributes (including key attributes), relationship sets and the cardinalities of all relationships.
(b)
Convert the ER diagram into a relational schema. For each relation list its attributes and indicate the primary key(s) and any foreign key(s).
(c)
Write an SQL statement that lists the **Name** of every customer who, in the month of March 2023, purchased goods whose total value after applying the appropriate membership discount exceeded ₦10 000.
(d)
Explain two advantages of normalising the above database to at least Third Normal Form (3NF).
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Question 6 View Details
A digital system requires a 4‑bit binary comparator that outputs a high signal (1) when the two 4‑bit numbers A₃A₂A₁A₀ and B₃B₂B₁B₀ are equal, otherwise it outputs low (0). In addition, the comparator must be enabled only when a control signal **Enable (E)** is high; when E = 0 the output must be forced to 0 regardless of the inputs. The design must use **only 2‑input NAND gates**.
Question Parts
(a)
Derive the Boolean expression for the equality detection of the two 4‑bit numbers using the basic operators AND, OR and NOT. Show the intermediate steps.
(b)
Transform the expression obtained in part (a) into a form that uses **only NAND operations**. Show the Boolean algebra steps or use De Morgan’s laws where appropriate.
(c)
Determine the minimum number of 2‑input NAND gates required to implement the complete circuit (including the Enable control). Justify your count.
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Question 7 View Details
A secondary school has recently installed a computer network that connects all its computers and provides internet access for teaching and learning. Since the installation, three incidents have been reported: (i) a student accessed a colleague’s personal email without permission, (ii) a staff member downloaded copyrighted music using school bandwidth, and (iii) an external hacker breached the school’s server and installed ransomware that encrypted several files.
Question Parts
(a)
Identify and discuss the ethical principles that are violated in each of the three incidents.
(b)
Propose a comprehensive security policy for the school’s network that addresses the identified ethical issues. Include at least three specific measures.
(c)
Explain how the proposed policy aligns with the Nigerian Cybercrimes (Prohibition, Prevention, etc.) Act 2015 and the role of the Nigerian Computer Emergency Response Team (ngCERT) in handling such incidents.
(d)
Evaluate the potential consequences (both positive and negative) of implementing the proposed security policy on the school’s teaching and learning environment.
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Question 8 View Details
A community health centre in a rural Nigerian town has introduced a mobile health (mHealth) application to record patient appointments, send medication reminders, and collect health statistics. After six months the centre recorded the following summary data: total registered patients = 1,200; average monthly appointments = 350; medication‑reminder compliance rate = 68%; number of reported data‑entry errors per month = 12; average time saved per staff member per day = 15 minutes.
Question Parts
(a)
Calculate the total amount of staff time saved in hours over the six‑month period. Show all working steps.
(b)
The centre wishes to raise the medication‑reminder compliance rate to at least 85 % within the next year. Propose a data‑driven strategy using the mHealth app that could achieve this target. Include at least two specific actions and explain how they would be monitored.
(c)
Discuss two potential ethical concerns associated with the use of the mHealth application in this context and suggest a mitigation measure for each concern.
(d)
Assuming the centre upgrades the app to automatically flag patients who have missed their appointments, outline an algorithm (in pseudocode) that could be used to generate the daily flag list.
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