Analysing an area of computer science

Practice

Recall it first, then use it — testing yourself builds the memory, where rereading the notes above only feels easier.

Recall and application shuffled together — you have to work out what each item wants before you can answer it, which is the part the exam actually tests. Both kinds feed the same spacing schedule, so anything you miss comes back sooner.

Say the answer out loud before flipping — that attempt is where the learning happens, even when you get it wrong.

Exam-style only. Instant feedback, shuffled each attempt, best score saved on this device.

What actually comes up

Three of the six areas are offered each year, and you choose ONE. The literal task structure has also changed: 2022 was a single long area-specific question (parts a–g, no shared second section); 2025 splits into a shorter Part One (your chosen area, with resource-booklet questions) and a shared Part Two (four questions, the same for every area — significance, two algorithms, real-world use, effects on people). Read the current year's instructions rather than assuming either shape.

Across 3 years

The pattern — what to prepare

The 2025 paper ↗ Marking schedule ↗

Part One — Computer Graphics (if chosen)

Points A, B, C on a grid are transformed to D, E, F using translation, scaling, or rotation; the origin (0,0) is at the centre, positive right and up.

• Line to draw with Bresenham's algorithm: from (2,1) to (9,4)

• a Enter the vectors needed to transform points A, B, C to D, E, F, name the type of transformation, and give an example of where it is used in computer graphics. Achieved
• b Using one of the two algorithms in the resource booklet, calculate the points that would be drawn between (2,1) and (9,4). Achieved
• c Plot the calculated points between (2,1) and (9,4) on the grid provided. Achieved
• d Explain why Bresenham's algorithm is better in computer graphics than using the simple y = mx + b formula for drawing a line. Merit

Part Two — shared by every area

Answer using whichever area you chose in Part One.

• a Discuss the significance of your chosen area within the broader field of computer science. Why is it considered a critical component of the discipline? Merit
• b Identify TWO specific algorithms or mechanisms central to your chosen area. For each, explain how it functions and discuss why it is important to the field. Merit
• c Explain how your chosen area is applied and implemented in a real-world scenario, with detailed examples of what it can do and what its limits are. Merit
• d Discuss how the issues and opportunities associated with your chosen area can impact society — benefiting certain groups while disadvantaging or negatively impacting others. Excellence

The 2022 paper ↗ Marking schedule ↗

Question One — Formal Languages (if chosen)

A DFA is described by the five-tuple (Q, Σ, δ, q0, F); a specific DFA with states S1–S4 and transitions on symbols W, X, Y, Z is given as Figure 1.

• DFA tuple: (Q, Σ, δ, q0, F)
• Regex given: [CFR]an
• Language HH: n zeros followed by the same number of ones

• a Complete the transition table for the DFA in Figure 1, and identify which of four given strings are NOT accepted by it, explaining your reasoning. Achieved
• b Given the regular expression [CFR]an and a syntax table, identify which words from a list it matches, and write a new regular expression that matches a different given list of words. Achieved
• c Identify the non-terminal and terminal symbols in a given context-free grammar, and give the expression built by a specific sequence of productions. Merit
• d Using examples, explain the relative capabilities and limits of the formal languages you have studied. Merit
• e Is it possible to create a finite state automaton for the language HH? Explain your answer by identifying the key problem related to regular languages, and how it is worked around. Excellence
• f A friend building a game wants enemy sprites to chase the player. Explain how your understanding of FSMs and formal languages could help, and discuss where else formal languages are used and how they affect people. Excellence

The 2021 paper ↗ Marking schedule ↗

Question One — Formal languages (if chosen)

Figure 1 gives a finite-state machine; later parts supply a table of common regular expressions, a context-free grammar, and a choice between a finite-state automaton that outputs a symbol on every transition (Figure 2, where "0/1" means "on a 0, output a 1") and a non-deterministic finite-state automaton (Figure 3, which accepts "b" and "bab" but not "bbab").

• a i From the machine in Figure 1: what is its alphabet? Achieved
• a ii From the machine in Figure 1: what is the label of its accepting state? Achieved
• a iii From the machine in Figure 1: what is the shortest string it accepts? Explain your answer. Achieved
• a iv Can "11011" be considered an accepted string? Explain your answer. Achieved
• a v Does this machine accept a string that is the digit "0" repeated 931 times? Explain your reasoning. Merit
• b For the regular expression [A-Z]{3}\d{3}, give TWO strings it would accept, and explain how you came to that conclusion. Achieved
• c Show the sequence of productions you would use to build the expression (–3). Achieved
• d Give a practical example of how formal languages are regularly used by people, and explain how problems can arise when using them that way. Merit
• e Summarise the similarities and differences between regular languages and context-free languages, explaining the capabilities of each and the limits of what they can do. Merit
• f Choose the transducer-style automaton (Figure 2) or the non-deterministic automaton (Figure 3). Explain what your chosen machine does, or could do, giving relevant example strings. Excellence

Question Two — Network communication protocols (if chosen)

Refers to Resources A to D in a separate booklet, and to a statement that networked devices grew from about 8.4 billion in 2018 to a forecast 29.3 billion by 2023, with 71% of the world mobile subscribers by then.

• a Name TWO application layer protocols and TWO transport layer protocols, and state the function of each. Achieved
• b Give examples of the ways you use network communication protocols. Achieved
• c i What are the capabilities and limitations of a network communication protocol you have investigated this year? Merit
• c ii Explain how the limitations you identified could be addressed. Merit
• d For email and for videoconferencing, explain why TCP and / or UDP would be used, commenting on the advantages and limitations of the protocol in each case. Merit
• e Given that forecast growth, what future uses or improvements do you think will be necessary in network communication protocols? Excellence

Question Three — Big data (if chosen)

Refers to Resources E to G in the booklet, and to a statement that about 2.5 × 10¹⁸ bytes of data are created daily.

• a Briefly describe the "3 Vs" of big data — volume, variety and velocity. Achieved
• b What key problems or issues relating to the 3 Vs can you see with the collection of the dataset used to generate Resources E and F, and how might they be addressed? Achieved
• c With reference to Resources E to G, how do the technical capabilities and limitations of big data affect people's lives? Give examples. Merit
• d What are the benefits and disadvantages of big data? Discuss whether you think it is possible to find a balance between them. Merit
• e Discuss how a particular organisation or technology sector you have studied uses big data, what future uses or improvements are possible, and what their implications are. Excellence

Three task documents exist and all three are transcribed above: 2021, 2022 and 2025. NZQA published no exam task for 2023 or 2024 — only their assessment schedules, which confirm Computer graphics, Big data and Network communication protocols were offered in 2023, and Big data, Complexity and tractability and Network communication protocols in 2024. That is where the area-rotation pattern above comes from.

Past exams & resources

⏱ Timed opens the paper and starts a countdown matching the exam length. Official NZQA PDFs. If a link 404s, that year’s paper may sit under a slightly different code: browse the NZQA subject page.