Topic: Big data and web architecture. Source: NESA 2025 HSC exam marking guidelines.
Question
A streaming service has exclusive rights to broadcast a live event each Sunday afternoon. Explain how the streaming service can use metadata and data mining to prevent technical difficulties during the broadcast of this weekly event. (3 marks)
Marking criteria (NESA)
3: Explains how metadata and data mining can be used to prevent technical difficulties during the broadcast. 2: Outlines how metadata AND/OR data mining can be used. 1: Identifies a feature of metadata or data mining.
Model answer (NESA sample answer / MG)
Metadata describes the content, structure and meaning of raw data, enabling more effective, accurate and efficient data mining. Data mining identifies user preferences and viewing patterns from large datasets, helping streaming services personalise recommendations and identify times of predicted high demand. Streaming service management uses this along with real-time user data to balance server loads and deliver smooth playback experiences.
Note: Marker feedback: show how metadata and data mining RELATE; address them separately; focus on technical difficulties and PREVENTION.
Outline TWO benefits of adding CSS to the company's website. (2 marks)
Marking criteria (NESA)
2: Outlines TWO benefits. 1: Some relevant information.
Model answer (NESA sample answer / MG)
It can provide the same look and feel across the company's websites for consistency and ease of use. Separate html and CSS code can allow developers to work independently on files.
sample-q12a (3 marks, short answer (explain, max 75 words))
Explain how a web developer could test a website for cross-platform compatibility. (3 marks, max 75 words)
Marking criteria (NESA)
3: Explains how a developer could test a website for cross-platform compatibility. 2: Outlines how, OR identifies strategies. 1: Some relevant information.
Model answer (NESA sample answer / MG)
A web developer can use browser developer tools. These tools, built into most modern browsers, allow developers to simulate how their website looks and behaves on different devices and screen sizes. By using these tools, developers can identify and fix any issues related to cross-platform compatibility, ensuring that the website works well across a variety of devices and browsers.
Note: Answers could include: online tools built specifically for cross-platform testing; manual testing on different devices and browsers; validating the code with the W3C Markup Validation Service.
Question(NESA did not publish the exact wording; this is reconstructed from the marking guideline)
[Question stem not available as text (it is on the interactive NESA familiarisation site). Task per the NESA mapping grid: how the load time of a web page can be improved (stimulus: page source with large images, multiple CSS files and a JavaScript file image-gallery.js at the top)]
Marking criteria (NESA)
4: Explains how the load time of the web page can be improved. 3: Outlines how some issues affecting load time can be resolved. 2: Identifies issues affecting load time OR outlines how to resolve ONE. 1: Some relevant information.
Model answer (NESA sample answer / MG)
The images can be resized to 640 x 480 beforehand so that the webpage does not need to load the large 4000 x 3000 images. The multiple CSS style sheets could be converted into a single .css file, reducing the number of HTTP requests the browser needs to send. If the "image-gallery.js" JavaScript file at the top of the source code loads slowly, it can be moved to the bottom just above
so that it will not block the rest of the page from loading.
Note: Answers could include: if image-gallery.js loads slowly, add the 'async' attribute to the tag so it loads in parallel with the rest of the page.
(b) Outline TWO ways, other than the use of a PWA, to minimise the load time of this weather app. (3 marks)
Marking criteria (NESA)
3: Outlines TWO ways, other than a PWA, to minimise load time. 2: Outlines ONE way, OR identifies TWO ways. 1: Some relevant information.
Model answer (NESA sample answer / MG)
One way would be to provide the option to select lower resolution images or text only display. Another way would be to utilise caching as this would provide high speed access to commonly requested weather data.
Note: Marker feedback: give ways to MINIMISE load times, not ways to investigate load times.
hsc2025-q9 (1 marks, matching table (tick which approach))
Question(NESA did not publish the exact wording; this is reconstructed from the marking guideline)
Match each characteristic to ORM, SQL, or both: (1) Code is focused on object manipulation; (2) Tables can be joined to enhance searching; (3) Programmers can choose the language used to access the database. [Characteristics as printed in the MG answer table; the question's introductory wording is not published.]
Marking criteria (NESA)
1: Correctly matches each characteristic to the appropriate approach.
Model answer (NESA sample answer / MG)
(1) ORM only. (2) Both ORM and SQL. (3) ORM only.
Note: Read from the MG table layout: row 2 has two ticks; rows 1 and 3 have one tick in the ORM column.
A weather app is to be designed to display real-time updates such as: rain commencing within the next 10 minutes; weather event warnings and warning cancellations; location specific weather conditions. (a) Compare the use of a progressive web app (PWA) with an interactive website, for delivering this weather app. (3 marks)
Marking criteria (NESA)
3: Compares the use of a PWA with an interactive website for the weather app. 2: Outlines features of a PWA and/or interactive website. 1: Identifies a feature of a PWA or an interactive website.
Model answer (NESA sample answer / MG)
Both PWAs and interactive websites are platform-independent, allowing users to access the app on any device with a browser. PWAs can pre-cache updates to enable offline updates when a stable internet connection is not available but may not provide real time updates for the most recent changes to weather or warnings. Meanwhile, interactive websites require a constant internet connection to provide any updates.
Note: Answers could include: some PWAs prompt for initial installation or setup which might deter some users. Marker feedback: link to the scenario (location, weather updates, notifications); use a common characteristic to show similarity/difference; give features specific to a PWA or interactive website, not general terms. NOTE: the NESA mapping grid lists 16(a) as load times and 16(b) as PWAs, but the MG body and the sample full-mark responses show 16(a) = PWA compare, 16(b) = load time.
sample-q12b (3 marks, short answer (explain, max 75 words))
Topic: Progressive web apps and load time. Source: NESA Sample Exam marking guidelines.
Question
Explain how the load time of a web page can be improved using a progressive web app (PWA). (3 marks, max 75 words)
Marking criteria (NESA)
3: Explains how load time can be improved using a PWA. 2: Outlines some features of a PWA and/or issues affecting load time. 1: Some relevant information.
Model answer (NESA sample answer / MG)
A progressive web app (PWA) can improve load times by pre-caching important resources, allowing files such as image-gallery.js and video-gallery.js to be loaded into memory or cache while the rest of the page loads. PWAs also use service workers to cache resources, ensuring faster load times on repeat visits and offline functionality. Background synchronisation and background fetching can update content in the background, so users see the latest information without slowing down the initial load.
Note: The sample answer refers to image-gallery.js and video-gallery.js: the original question appears to have had a stimulus not in the printout.
sample-q13 (3 marks, short answer (describe, max 75 words))
Describe the function of protocols in the transfer of data. In your answer, refer to a specific web protocol. (3 marks, max 75 words)
Marking criteria (NESA)
3: Describes the function of protocols in the transfer of data, with reference to a specific web protocol. 2: Describes the function OR provides an example of a web protocol and its use. 1: Some relevant information.
Model answer (NESA sample answer / MG)
Protocols are important in data transfer as they establish rules for communication between devices connected to a network, such as the internet. HTTP (Hypertext Transfer Protocol) enables browsers to request web content from servers, which respond with the requested data. The protocol defines the structure of requests and the response so that data transfer can occur.
Note: Answers could include: TCP/IP, DNS, FTP/SFTP, SSL/TLS, SMTP/POP3/IMAP, data packets.
Question(NESA did not publish the exact wording; this is reconstructed from the marking guideline)
[Question stem not available as text (it is on the interactive NESA familiarisation site). Task per the NESA mapping grid: give the output of an SQL query on a product table, including correct ordering of rows]
Marking criteria (NESA)
2: Correct output for the SQL query, including the correct ordering of the rows. 1: Some relevant information.
A table Students(StudentID, FirstName, Surname, Attended, Level) tracks students at a coding club (12 rows; levels Beginner, Intermediate, Expert). Complete the SQL query to generate the number of students at each level: SELECT Level, ??? FROM Students ??? BY Level;
Marking criteria (NESA)
2: Correctly completes the SQL query. 1: Correctly selects at least TWO correct options.
Model answer (REASONED, not copied: the official answer was an image)
SELECT Level, COUNT(StudentID)
FROM Students
GROUP BY Level;
Note: REASONED (not copied): the MG answer is an image/table that could not be extracted. The dropdown option list is not extractable. COUNT() is also valid.*
A shop uses an online database with a Products table (ProductID, Name, Price, Mass, Producer, Quantity, SupplierID) and a Suppliers table (SupplierID, Name). The prices are in dollars and the masses are in grams. The shop wants to identify all the products with a mass of at least 50 grams that are produced by Yumtreats. Write an SQL query to display the product names and supplier names, in descending order by product name. (3 marks)
Marking criteria (NESA)
3: Correct SQL query. 2: Addresses some of the requirements. 1: Some understanding of SQL.
Model answer (NESA sample answer / MG)
SELECT Products.Name AS 'Product', Suppliers.Name AS 'Supplier'
FROM Products, Suppliers
WHERE Products.SupplierID = Suppliers.SupplierID
AND Products.Producer = 'Yumtreats'
AND Products.Mass >= 50
ORDER BY Products.Name DESC
Note: An INNER JOIN ... ON equivalent is equally valid. Quote text values. Both tables have a column called Name, so qualify them (Table.Name).
Question(NESA did not publish the exact wording; this is reconstructed from the marking guideline)
[Question stem not available as text (it is on the interactive NESA familiarisation site). Task per the NESA mapping grid: write a SQL query over Customers, Products and Orders showing customer, product and quantity with renamed columns, ordered by OrderID]
Marking criteria (NESA)
3: Correct SQL query. 2: Substantially correct query with at least TWO of: renaming the columns; selecting the three tables; joining the tables. 1: Some understanding of renaming the columns or joining the tables.
Model answer (NESA sample answer / MG)
SELECT Customers.CustName as 'Customer', Products.ProductName as 'Product',
Orders.OrderQuantity as 'Quantity'
FROM Products, Customers, Orders
WHERE Orders.ProductID = Products.ProductID
AND Orders.CustID = Customers.CustID
ORDER BY Orders.OrderID ASC
Below is the Issues table for a technical support company. FixTime, in minutes, is the time taken to complete each job. [table image not extractable: columns include JobID, Category, Status, FixTime] Construct a SQL query that displays: the number of pending software jobs; the number of pending hardware jobs; the number of escalated software jobs; the number of escalated hardware jobs. List the results in order from the highest to lowest, based on the number of jobs. (4 marks)
Marking criteria (NESA)
4: Correct SQL query that extracts 'Pending' and 'Escalated' jobs for the 'Software' and 'Hardware' categories, counts the jobs for each status in each category, and outputs results in descending order. 3: Addresses most requirements. 2: Some understanding of the problem. 1: Some understanding of SQL or the problem.
Model answer (NESA sample answer / MG)
SELECT Category, Status, COUNT(JobID) AS Jobs
FROM Issues
WHERE (Status = 'Pending' OR Status = 'Escalated')
GROUP BY Status, Category
ORDER BY Jobs DESC
Note: Note: the sample does not filter Category to Software/Hardware (the table is assumed to have only those two). Adding AND (Category = 'Software' OR Category = 'Hardware') is safe. Marker feedback: query must run; quotation marks around data being searched; use OR/AND in WHERE; correct GROUP BY and ORDER BY fields.
(b) Explain why server-side web programming would be needed to develop this website. Support your answer with examples from the website. (3 marks)
Marking criteria (NESA)
3: Explains why server-side web programming is needed, with examples from the scenario. 2: Outlines some features, with examples. 1: Identifies a feature and/or relevant examples.
Model answer (NESA sample answer / MG)
Server-side development will need to be used to provide dynamic information to the front-end (website). There are many dynamic aspects to the website, including the menu which changes along with subscription information and order tracking information. Server-side scripting will need to be written to read the relevant information from storage (most likely, a database) and then provide this information to the front-end.
Note: Marker feedback: key features of server-side programming plus stimulus examples; 'draw on the circular nature of data to link the backend to the front end'.