Without seeing the notification of the assessment task, I'm guessing that the difference comes down to secondary data versus first-hand data. The HSC Syllabus says that students need to develop both kinds of skills at Stage 6. To analyse secondary sources, you need to identify reliable sources, valid methods and accurate data. To analyse first-hand data, you need to come up with a reasonable hypothesis, select equipment and methods, risk analysis, sources of error and ways to minimise errors, accurate data processing and write a closing conclusion that answers the original hypothesis.