A Level Information Technology (ICT): Data Processing and Information — Practice Questions

These are original questions written for Marlbridge, for revision and practice on this content. They are not reproduced past-paper questions, and they do not replicate the exam’s exact structure, question count or mark tariffs — examination boards hold copyright in their own papers. Use these alongside the official past papers available free from your board.

Related: Data Processing and Information revision notes

These questions are for topic 1, Data processing and information (AS Level), of Cambridge International AS & A Level Information Technology (9626). Questions 4 and 5 are on databases, which the 2025–2027 syllabus places in topic 10 (Database and file concepts), not topic 1. They are kept here, labelled, for students revising both topics.

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Section A

1. Distinguish between data and information, giving an example of each, and state what turns data into information. [3]

2. State four factors that affect the quality of information. [4]

Section B

3. This question is about validation and verification.

(a) Describe four validation checks and give a suitable field for each. [8] (b) Describe two methods of verification. [4] (c) Explain why validation cannot guarantee that data is correct. [2]

4. (Topic 10, Database and file concepts.) Explain the difference between a flat file and a relational database, and give three advantages of a relational database. [5]

5. (Topic 10, Database and file concepts.) Explain the terms primary key, foreign key and referential integrity. [6]

6. Explain the difference between batch processing and online processing, giving one example system suited to each. [8]

Section C

7. Explain why data entry needs both validation and verification, rather than just one of them. [2]

8. A researcher can either run their own survey or use existing census data.

(a) State whether each is a direct or an indirect data source. [2] (b) Explain one advantage and one disadvantage of using the census data instead of running a new survey. [4]

9. Explain why payroll processing typically uses batch processing rather than real-time processing, and explain why an autopilot system could not use batch processing instead. [4]

10. A company’s staff connect from home to its internal network, and customers place orders on its website.

(a) Describe the difference between symmetric and asymmetric encryption. [2] (b) Identify which encryption protocol suits each connection, and explain your choice. [4]

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Answers

1. Data — raw facts and figures with no context, e.g. “42” [1]. Information — data given context and meaning, e.g. “42 students attended today’s class” [1]. Data becomes information when context and meaning are added [1].

2. Any four, e.g. accuracy, relevance, age (how up to date it is), level of detail, completeness — the five examples the syllabus gives [1] [1] [1] [1]. (Indicative marking written for this practice set, not official marking; other sensible factors could be credited.)

3. (a) Any four, 2 marks each: Range check — the value must fall between set limits; suitable for age or a percentage mark [1] [1]. Format (picture) check — the data must match a pattern; suitable for a postcode or a date [1] [1]. Presence check — the field must not be left blank; suitable for a surname or student ID [1] [1]. Type check — the data must be of the correct data type; suitable for a numeric quantity field [1] [1]. Length check — a set number of characters; suitable for a phone number [1] [1]. Check digit — a calculated digit appended to a code; suitable for a barcode or ISBN [1] [1]. (b) Double entry — the data is entered twice, by the same or different operators, and the two versions are compared by the computer; any difference is flagged [1] [1]. Visual (proofreading) check — the operator compares the data on screen against the original source document [1] [1]. (c) Validation only checks that data is sensible and of the right form, not that it is true [1]; an age of 35 entered for a 34-year-old passes every check but is still wrong [1].

4. A flat file stores all data in a single table, so the same information is repeated on many records [1]. A relational database stores data in several linked tables, related by key fields [1]. Advantages, any three [1] each, maximum [3]: reduced data redundancy — each fact is stored once, saving storage [1]; improved data consistency — an update is made in one place, so records cannot disagree with one another [1]; improved data integrity and security, since access rights can be granted table by table [1]; greater flexibility — new queries and reports can combine tables without restructuring the data [1]; easier maintenance and expansion [1].

5. Primary key — a field (or combination) that uniquely identifies each record in a table; no two records may share it and it cannot be null [1] [1]. Foreign key — a field in one table that refers to the primary key of another table, creating the relationship between them [1] [1]. Referential integrity — the rule that a foreign key value must always match an existing primary key value in the related table [1], which prevents “orphan” records such as an order attached to a customer who does not exist [1].

6. Batch processing collects transactions together and processes them all at a scheduled time, with no user interaction while running [1] [1]; suited to payroll, where there is a large volume of similar transactions and no need for an immediate response [1] [1]. Online processing processes each transaction immediately as it is entered, keeping the master file continuously up to date [1] [1]; suited to a seat-booking system, where two customers must never be able to reserve the same seat, which batching could allow in the gap before the file is updated [1] [1].

7. Validation only checks that data is reasonable, so a wrong but sensible value (e.g. a mistyped but possible date of birth) still passes [1]. Verification checks the data against the source or after transfer, so it catches copying and transmission errors that validation misses — but it cannot tell whether the data is sensible, or catch an error already on the source document, so both are needed [1].

8. (a) The researcher’s own survey is a direct source [1]; the census data is an indirect source, since it was collected for a different original purpose [1]. (b) Any one advantage: the census data is cheap and immediately available, and often covers a very large sample [1] [1]. Any one disadvantage: it may be out of date, in the wrong format for the researcher’s needs, or carry an unknown bias, since it was not designed for this specific research question [1] [1].

9. Payroll involves a large volume of similar transactions with no urgency, so it can be collected and processed together in a scheduled batch, e.g. overnight when the system is otherwise idle [2]. An autopilot is a real-time control system, where the output (an adjustment to the aircraft’s controls) must feed back to influence the very next input immediately — a delay of even a few seconds while data is batched would be unsafe, since the system must respond continuously to changing conditions [2].

10. (a) Symmetric encryption uses a single secret (private) key to both encrypt and decrypt, so the key must be shared securely [1]; asymmetric encryption uses a public key to encrypt and a matching private key to decrypt, so the private key never has to be sent [1]. (b) Staff connecting to the internal network: IPsec [1], because it encrypts and authenticates all traffic between the home device and the company network at the network layer, whatever application is used, as in a VPN [1]. Customers ordering on the website: TLS/SSL [1], because it secures the session between the customer’s browser and the web server and needs nothing installed by the customer beyond the browser [1].

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Common mistakes

• Confusing validation with verification.
• Giving a validation check without a suitable field.
• Saying a primary key “identifies the table” rather than each record.
• Confusing batch processing with online or real-time processing, or picking an example scenario unsuited to the method described.