This is an achieved level guide for students attempting data representation in digital technologies achievement standard 2.44 (AS91371). It is only suitable for students who aren't aiming to get more than achieved.

Note that this is the only guide you need to follow to satisfy the data representation requirements up to achieved. It covers two different data types - numbers and text.

In order to fully cover the standard, you will also need to have done projects covering the three encoding topics up to the achieved level (error control coding, encryption, and compression), and a project covering human computer interaction, and include these in your report.

The topic of Data Representation has the following achieved bullet point in achievement standard 2.44, which this guide covers.

Achieved: “describing ways in which different types of data can be represented using bits”

As with all externally assessed reports, you should base your explanations around personalised examples.

You should read and work through the interactives in the following sections of the CS Field Guide in order to prepare yourself for the assessed project.

Read all of these sections, as they give the necessary introduction of the topic

What’s the Big Picture?

Representing numbers with bits

Representing text with bits

Start this section by writing an introduction to the topic of data representation. Describe what a "bit" is, and why computers use bits to represent data. This introduction only needs to be a couple of sentences - you are just showing the marker that you understand what a "bit" is, and how "bits" are used to represent data. It must be in your own words, based on what you understood in class (e.g. do not paraphrase a definition).

Next, you are going to show an example of how the day and month (number form) of your birthday are represented in binary. If you don't want to include your real birthday in your report, you can make one up, but it must not be the same birthday that somebody else in your class is using. For each of the two numbers, show the working you use to get the binary representation, the final binary representation using 1's and 0's, and a description of what you did to get the binary representation.

Finally you are going to show one other type of representation - the ASCII representation, which is used to represent strings of text. You will do this by showing your first name and favorite food in ASCII. Find an ASCII table (there is one in the field guide). Now, use the table to convert both the words to ASCII. Briefly describe how you used the ASCII table to convert these words to ASCII. You should not include the ASCII table in your report.

  • Put a main heading for Data Representation (your report will also have main headings for Encoding and Human Computer Interaction) and subheadings for Representing Numbers and Representing Text. Be careful to put your explanations and examples under the correct headings.
  • Do not include large lists or tables, for example do not include an ASCII table or a list of binary number conversions.
  • This project should not take up more than 1 to 1½ pages in your report.

Removed from section on numbers in programming Languages