Not easy. Which is why “secret” is in the title. Copies are floating around in schools and, soon, social media. If someone links to such a social media copy in a comment I won’t object (but no one should upload to this site). VCAA will release it in a few days.
A nice exam within the constraints of the curriculum. The reference to significant figures in Q5 I did not expect, but it actually made sense in the context.
I anticipate a lot of comments that this was easier than 2024. I have no idea what the standard is for these papers and what is a “good” score.
If it is a question of whether or not the paper fairly covered the curriculum… I think it did. Which is nice to see.
I do see one possible issue – Q6b. There is something in the wording that I think may cause some confusion and/or a range of interpretations. I will let others give their opinion while I ponder it further…
“Easy” is a common refrain I’ve heard for quite a few maths/science VCE exams this year. I wonder if VCAA have intentionally relaxed the difficulty somewhat (or potentially just made the wording of the questions better) to dodge complaints.
Very good question (to which I have no clue of an answer). Easy exams are bad. But exams becoming easier because the wording is (finally) getting better is good.
“Easy exams are bad.” This prompted me to wonder “What is the purpose of an exam – or more generally – an assessment?”
A standard answer is that the purpose of assessment is to determine where the students is in his/her learning. Putting this in terms of a VCE examination, it might mean that the purpose of the examination is to assess how much the student has learned during Year 12.
In this context, another purpose is to give the students marks that can be used to contribute to the ATAR which will in turn be used to determine admission to a university or TAFE course.
And then there is the question, “easy for whom?” As Senor Wences said, “Deefeecult For You -Easy For Me”.
For question 6b,
there were people who used different ways of getting the final answer, which resulted in two different answers both 1 decimal place apart, do you think that VCAA would accept both answers
Study Design
– Seasonal adjustment including the use and interpretation of seasonal indices and their calculation using seasonal and yearly means
– If following the study design explicitly, then method 1 below would be most appropriate?
I think there are actually two different ways to interpret the question – thus leading to two different methods. The main issue/problem is that the question specifies the ninth month. Now… there are 48 months in the sample, does the question want the SI for just month 9, or the SI for September in general.
Different answers. Will be interesting to see if the examiner’s report mentions anything.
For what it is worth, I got the answer 0.588 but I’m not totally happy with this for the reasons given above. However, in answer to ChX1, yes, I think Method 1 best aligns with the study design algorithm for calculating SIs.
Purely based on wording, they surely meant the SI for September.
“A seasonal index can be calculated for each month based on the four-year period.
Calculate this seasonal index for September, the ninth month in the calendar year.”
It just seems like a general statement to lead the student to check the ninth month of each calendar year on the plot…
Yes that was my interpretation but the 9th month only really means the first September instance since the months are numbered 1 to 48.
If they had said 9, 21, 33 and 45 then there would have been no issue. If they had said September is the 9th month EACH YEAR, also no issue.
On the whole, not a big nit-pick but when you are in a hurry to push all those buttons, read all those words… these things can trip up even a good student.
I was somewhat hoping this issue would come up so I could question VCAA on it.
The AC8.4 that the states’ senior curricula are modelled on says
“calculate seasonal indices by using the average percentage method (ACMGM090)”
which QLD, Tas, WA, and ACT all use nearly identical wording to. VIC is the only one that change it to not mention “average percentage method” (instead only “using seasonal and yearly means”) which is your Method 2 that VCAA generally use as the solution in the exam reports for similar questions.
Your method 1 is the “simple averages” method which gives strikingly similar results, is significantly more efficient to calculate, but is not algebraically equivalent to “average percentage”, hence the minor differences in the SIs.
My issue, that I’ve only noticed recently, is that there’s a number of times they’ve examined this where they have essentially led students towards “simple averages” by giving long term averages of each season (2016 E1 Q14-16 which is included in the 2023 sample questions, 2020 E1 Q15-16, 2022 NHT E1 Q16, 2025 NHT E1 Q14-15) which will cause issues if they keep flip-flopping back and forth between the two methods.
My assumption is that they prefer “average percentage” because it feels like it should account for trends better, but if that was the issue, then they should instead use the ratio-to-trend method which strips the trend out first before calculating SIs.
To my understanding the “using seasonal and yearly means” is method 1 as it is finding the seasonal mean of September in all 4 years divided by the mean monthly sales of all 4 years (calculated from yearly means), so I am unsure if VCAA would be aware of this issue.
I would think that VCAA should accept both methods, and it would be rather disappointing if students lost 2 marks if they used one of the methods and got an answer 0.001 decimals apart
They have said that they were aware of both approaches when the question was set and both will be accepted as they are both valid ways to calculate a seasonal index over multiple years of data.
I guess that they will have to keep both methods in mind for all seasonal index questions over multiple years in future, or otherwise specify in the question what approach is required.
That’s very clunky, but perhaps they realised the ambiguity late in the piece. In which case it is much better to acknowledge the issue, rather than doing another Hungarian.
Wild horses couldn’t drag me to look at this problem, but I assume there is some natural way to word such questions to make clear which method is intended?
“A seasonal index can be calculated for each month based on the four-year period.”
they could have said something to the effect of
“A seasonal index can be calculated for each month by averaging the seasonal indices for each of the four years for that month.”
(could be better tbh, but does the job)
or, for the other method
“A seasonal index can be calculated for each month by using the long-term average value for that month.”
or otherwise “by using the average percentage/simple averages method”
but VCAA would need that defined somewhere like the other states, but they don’t.
The “can be calculated” is also bothering me a little. Should probably be “is to be calculated” or “is calculated”.
There is a question looking at multiple years in 2019 Exam 2 Q6. I tried chX1’s method 1 and got the correct answers rounded to 2 dp. However looking at the examination report for the unrounded value for autumn, they have used Method 2, which matches most text books of treating multiple years separately when calculating SI and then averaging corresponding season’s SI.
I found the exam more straight forward than previous years. Less ‘head scratcher’ questions where you have to really unpack the concept to figure out how to solve it. However, there were lots of ways to make small silly errors and a higher number of ‘explain’ style questions than normal (VCAA trying to get around the calculator programs I assume). I really dislike the template they use for writing equations and recurrence relations that has the plus sign in between the two boxes, but the value is negative.
There is also a question finance and recursion with filling in an amortisation table that is prompting debate over rounding. Curious to see VCAA’s response there.
Yes I noticed that too about the amortization table question balance. Students who calculated by hand and rounded each step I would say will have the correct answer. Using the amortization calculator on the CAS will be higher by 1 cent. However they may pay both. Time will tell.
Yes, I always teach to calculate from the starting value as you can check the other values in the table to make sure you are correct. I would also say that it is more accurate as the bank is calculating based off unrounded values. A lot of students find this very tricky – keep unrounded values for calculations but write down rounded values. Will be interesting to see what the marking guide says.
I now know of 4 students (from a large but high acheiving cohort) who missed the ‘complete the amortisation table’ (Q7c) entirely. The formatting on this question isn’t great with the question not being the final line of the text and the next question below very close and also referring to the table. For questions where students complete a graph they usually have a bolded instruction below to say complete on graph above. Frustrating when there was plenty of room on the page to format the question more clearly.
Where does one find a copy of the exam ?
Not easy. Which is why “secret” is in the title. Copies are floating around in schools and, soon, social media. If someone links to such a social media copy in a comment I won’t object (but no one should upload to this site). VCAA will release it in a few days.
A nice exam within the constraints of the curriculum. The reference to significant figures in Q5 I did not expect, but it actually made sense in the context.
I anticipate a lot of comments that this was easier than 2024. I have no idea what the standard is for these papers and what is a “good” score.
If it is a question of whether or not the paper fairly covered the curriculum… I think it did. Which is nice to see.
I do see one possible issue – Q6b. There is something in the wording that I think may cause some confusion and/or a range of interpretations. I will let others give their opinion while I ponder it further…
“Easy” is a common refrain I’ve heard for quite a few maths/science VCE exams this year. I wonder if VCAA have intentionally relaxed the difficulty somewhat (or potentially just made the wording of the questions better) to dodge complaints.
Very good question (to which I have no clue of an answer). Easy exams are bad. But exams becoming easier because the wording is (finally) getting better is good.
“Easy exams are bad.” This prompted me to wonder “What is the purpose of an exam – or more generally – an assessment?”
A standard answer is that the purpose of assessment is to determine where the students is in his/her learning. Putting this in terms of a VCE examination, it might mean that the purpose of the examination is to assess how much the student has learned during Year 12.
In this context, another purpose is to give the students marks that can be used to contribute to the ATAR which will in turn be used to determine admission to a university or TAFE course.
And then there is the question, “easy for whom?” As Senor Wences said, “Deefeecult For You -Easy For Me”.
For question 6b,
there were people who used different ways of getting the final answer, which resulted in two different answers both 1 decimal place apart, do you think that VCAA would accept both answers
Study Design
– Seasonal adjustment including the use and interpretation of seasonal indices and their calculation using seasonal and yearly means
– If following the study design explicitly, then method 1 below would be most appropriate?
Method 1
https://drive.google.com/file/d/1wZ5nLDGm_jNSfwrsy5nBy6_nBKBVZDWB/view
Method 2
https://drive.google.com/file/d/1LxruJehmBH2yhDST76K8tYkbH1CdT4el/view?usp=sharing
Thanks, ChX1. I have not seen the paper, and would probably not be able to help even if I had, but presumably readers will chime in shortly.
I think there are actually two different ways to interpret the question – thus leading to two different methods. The main issue/problem is that the question specifies the ninth month. Now… there are 48 months in the sample, does the question want the SI for just month 9, or the SI for September in general.
Different answers. Will be interesting to see if the examiner’s report mentions anything.
For what it is worth, I got the answer 0.588 but I’m not totally happy with this for the reasons given above. However, in answer to ChX1, yes, I think Method 1 best aligns with the study design algorithm for calculating SIs.
Purely based on wording, they surely meant the SI for September.
“A seasonal index can be calculated for each month based on the four-year period.
Calculate this seasonal index for September, the ninth month in the calendar year.”
It just seems like a general statement to lead the student to check the ninth month of each calendar year on the plot…
Yes that was my interpretation but the 9th month only really means the first September instance since the months are numbered 1 to 48.
If they had said 9, 21, 33 and 45 then there would have been no issue. If they had said September is the 9th month EACH YEAR, also no issue.
On the whole, not a big nit-pick but when you are in a hurry to push all those buttons, read all those words… these things can trip up even a good student.
I was somewhat hoping this issue would come up so I could question VCAA on it.
The AC8.4 that the states’ senior curricula are modelled on says
“calculate seasonal indices by using the average percentage method (ACMGM090)”
which QLD, Tas, WA, and ACT all use nearly identical wording to. VIC is the only one that change it to not mention “average percentage method” (instead only “using seasonal and yearly means”) which is your Method 2 that VCAA generally use as the solution in the exam reports for similar questions.
Your method 1 is the “simple averages” method which gives strikingly similar results, is significantly more efficient to calculate, but is not algebraically equivalent to “average percentage”, hence the minor differences in the SIs.
My issue, that I’ve only noticed recently, is that there’s a number of times they’ve examined this where they have essentially led students towards “simple averages” by giving long term averages of each season (2016 E1 Q14-16 which is included in the 2023 sample questions, 2020 E1 Q15-16, 2022 NHT E1 Q16, 2025 NHT E1 Q14-15) which will cause issues if they keep flip-flopping back and forth between the two methods.
My assumption is that they prefer “average percentage” because it feels like it should account for trends better, but if that was the issue, then they should instead use the ratio-to-trend method which strips the trend out first before calculating SIs.
Thank God this is not my turf.
To my understanding the “using seasonal and yearly means” is method 1 as it is finding the seasonal mean of September in all 4 years divided by the mean monthly sales of all 4 years (calculated from yearly means), so I am unsure if VCAA would be aware of this issue.
I would think that VCAA should accept both methods, and it would be rather disappointing if students lost 2 marks if they used one of the methods and got an answer 0.001 decimals apart
I have emailed them to confirm and will report back if/when I get a response.
Thanks, Alex.
They have said that they were aware of both approaches when the question was set and both will be accepted as they are both valid ways to calculate a seasonal index over multiple years of data.
I guess that they will have to keep both methods in mind for all seasonal index questions over multiple years in future, or otherwise specify in the question what approach is required.
Thanks very much, Alex.
That’s very clunky, but perhaps they realised the ambiguity late in the piece. In which case it is much better to acknowledge the issue, rather than doing another Hungarian.
Wild horses couldn’t drag me to look at this problem, but I assume there is some natural way to word such questions to make clear which method is intended?
Instead of saying
“A seasonal index can be calculated for each month based on the four-year period.”
they could have said something to the effect of
“A seasonal index can be calculated for each month by averaging the seasonal indices for each of the four years for that month.”
(could be better tbh, but does the job)
or, for the other method
“A seasonal index can be calculated for each month by using the long-term average value for that month.”
or otherwise “by using the average percentage/simple averages method”
but VCAA would need that defined somewhere like the other states, but they don’t.
The “can be calculated” is also bothering me a little. Should probably be “is to be calculated” or “is calculated”.
Thanks Alex, will have to review this and consider how to update our teaching for this topic for next year.
There is a question looking at multiple years in 2019 Exam 2 Q6. I tried chX1’s method 1 and got the correct answers rounded to 2 dp. However looking at the examination report for the unrounded value for autumn, they have used Method 2, which matches most text books of treating multiple years separately when calculating SI and then averaging corresponding season’s SI.
I don’t think Method 1 is addressing the definition of seasonal index on the formula sheet.
Recall that
If you use the average from the four september sale numbers, it is not *the actual value* in the numerator.
Will also be interested to see what VCAA will say on this.
I’m almost certain they will be wanting method 2. It was just interesting to see method 1 get very close to the same answer.
I found the exam more straight forward than previous years. Less ‘head scratcher’ questions where you have to really unpack the concept to figure out how to solve it. However, there were lots of ways to make small silly errors and a higher number of ‘explain’ style questions than normal (VCAA trying to get around the calculator programs I assume). I really dislike the template they use for writing equations and recurrence relations that has the plus sign in between the two boxes, but the value is negative.
There is also a question finance and recursion with filling in an amortisation table that is prompting debate over rounding. Curious to see VCAA’s response there.
Thank you. Please include a name when commenting. (A fake name is fine.)
Yes I noticed that too about the amortization table question balance. Students who calculated by hand and rounded each step I would say will have the correct answer. Using the amortization calculator on the CAS will be higher by 1 cent. However they may pay both. Time will tell.
Yes, I always teach to calculate from the starting value as you can check the other values in the table to make sure you are correct. I would also say that it is more accurate as the bank is calculating based off unrounded values. A lot of students find this very tricky – keep unrounded values for calculations but write down rounded values. Will be interesting to see what the marking guide says.
I now know of 4 students (from a large but high acheiving cohort) who missed the ‘complete the amortisation table’ (Q7c) entirely. The formatting on this question isn’t great with the question not being the final line of the text and the next question below very close and also referring to the table. For questions where students complete a graph they usually have a bolded instruction below to say complete on graph above. Frustrating when there was plenty of room on the page to format the question more clearly.
Thanks, Berni. Not sure I’m able to judge well but I’ll look, and others may comment.