A commonly expressed opinion of Year 11/12 students is that they will achieve a higher ATAR if they study Standard Mathematics rather than the higher Mathematics course. Each year a report is issued by the UAC that provides statistics on the HSC and Scaled marks for all subjects. I have written a note ('Scaling of the 2019 Mathematics exams' available at www.kenderdinemathstutoring.com.au/downloads) that looks at the results for all Mathematics courses in 2019. Interestingly for Standard Mathematics, 75% of students scored less than 80% in the HSC but the corresponding Scaled mark was 60%. A Band 6 result was achieved by only 5% of Standard Mathematics students compared to 24% of Mathematics students.

Here is the cumulative percentage plot:

The horizontal distance is the difference between the HSC mark (blue) and Scaled mark (green) for each cumulative percentage. The reduction is quite marked.

Here is the paired bar chart for the distribution of students' marks in Bands for both Standard Mathematics and Mathematics. While the distribution is approximately symmetrical for Standard Mathematics, that for Mathematics is skewed toward the higher Bands.