WitCH 28: Tone Deaf

We haven’t yet had a chance to go through the 2019 VCE exams, but this question was flagged to me independently by two colleagues: let’s call them Dr. Death and Simon the Likeable. It’s from Mathematical Methods Exam 2 (CAS). (No link yet.)

39 Replies to “WitCH 28: Tone Deaf”

  1. 3e: I don’t understand how there’s a transformation in terms of x applied to a function in terms of t. And wouldn’t there also be an infinite number of solutions for a, b, c, d?

  2. Also, isn’t 3e grammatically senseless? An integral doesn’t have an area, it has a value. Whether or not that value represents an area is another matter entirely. Maybe?

    1. Those were my thoughts too, Red Five. And even if you admit a charitable reading of the question, then you’re confronted with what Tau says above.

    1. RF, I’m not really concerned about EAL students for now. I don’t think EFL students have a hope of making sense of this garbage.

  3. Coming back to this question there are a few big problems (and probably a really big, fundamental one that I’ve somehow missed…):

    The variable x is never defined since the original function has dependent variable t. OK, perhaps students will just miss this issue in their rush to push buttons and solve the equations. VCAA would not be forgiving of students if they wrote x instead of t however!
    Why do the integrals need to be 2 to 0 and 2 to 6, why can’t they be 0 to 2 and 6 to 2? If absolute value functions hadn’t been (for some reason known only to VCAA) removed from the methods course, the translation would be simpler, surely?
    Finally, surely it is just a case of a=b=1, d=0 and c=some general solution with a +8k in the answer?

        1. Hopefully some time this year. The delay is an absolute disgrace – the NSW reports get published within weeks of the exam.

          I think VCAA is still trying to figure out where the word ‘the’ should go in its gutless “All students given mark” comment – this time for MCQ 12.

          1. Most other states publish their reports within days. NSW is interesting, they publish two sets of reports from what I can see, the “solutions” and the “marking guide”. Different way of marking, too. VCAA could learn a lot… but won’t.

            1. VCAA will never publish their marking guide. VCAA has too much to hide, publishing the marking guide would expose it to too much risk. What I don’t understand is why teachers think that things like Meet the Asses are useful. None of those asses will ever say anything worthwhile – they certainly won’t comment on the marking guide. Any meaningful question is met with “I can’t tell you that”, “I don’t know that” etc. All they give is a preview of the Examination Report – maybe that’s why the reports come out so late, it’s a cosy arrangement to make gravy trains like Meet the Asses look worthwhile …?

              1. Meh. Its a day off work to catch up with other teachers I only see at these things or MAVCON (which I’ve stopped going to/presenting at anyway). Its PD hours and a few laughs (privately, to myself of course, although at a recent SAC workshop I will admit to not being able to contain myself during the prob and stats presentation…)

                1. Yes, that explains meeting the asses during the day (and has been said in other posts). However, many of these sessions run in the evening – who wants to waste their time meeting asses in the evening (unless they’ve been suckered into it??)

                  1. I don’t go to those. At my school it seems to be the first time teachers of a subject that ask to go… Some teachers seem to think it is good for SAC 1 ideas in MM and SM. I’m a lot less certain about the merits.

              2. JF, I’m in two minds about the assessors. They’re not responsible for the idiot culture of the VCAA, and they don’t make the idiot rules that result. On the other hand, when they sign up to be assessors they either know the VCAA culture is idiotic with idiot rules, or they don’t; either assumption is then a basis for criticism.

                1. I’d posit that every assessor knows the culture they’ve implicitly signed up to. That’s on their own conscience. What really shits me are the ones who then present at things like Meet the Asses, duping attendees into thinking they’re going to get the inside scoop on how the exams were marked.

                  Maybe this is why the MAV now provides solutions written by those asses, so that attendees think they’re leaving with something snort valuable (from the solutions I’ve seen, I’m tempted to retract this sentence. The freely available itute solutions are superior and more reliable – they consistently flag when a VCAA question is defective).

                  (If the MAV had integrity, it would include a clear disclaimer stating that the asses who present are bound by confidentiality agreements with VCAA not to discuss marking schemes or anything else that won’t be in the Examination Report. But that’s not good for business).

                  1. Well, JF, I still think you’re probably being a little (but only a little) too hard on the assessors.

                    There’s no question that every assessor, and every teacher and every student, is fully aware of the Little Hitler culture of VCAA grading. It is not at all obvious, however, that the assessors realise how pointless and how damaging is this Little Hitlerism. Such pettiness is extremely common in mathematics teaching, in both schools and universities.

                    I think it’s worth a whole blog post but, in brief, I think such (lack of) thinking stems from a fundamentally weak sense of mathematics. Without a clear understanding of the way mathematics works, one clings desperately to the “rules”. Any good teacher recognises that kind of fear in some (way too many) students, but the exact same fear is evident in some (way too many) teachers and administrators and textbook writers and university lecturers.

                    For similar reasons, it is also not clear to me that the assessors realise just how much is wrong in VCE mathematics, both in specific fact and in general sense. The assessor solutions and the few assessor meetings I’ve attended suggest to me they are simply not sufficiently strong in mathematics to realise the fundamental third-ratedness of VCE mathematics.

                    In summary, forgive them a little, for they know not what they do. But, as for the super-cosy MAV-VCAA “Meet the Assessors” partnership, yes, that is repugnant.

                  2. JF:
                    Thanks for indicating the over-due published Exam 2 Assessor’s report.
                    We all have seen the “adjusted exam specification” as well as “Adjusted Formula Sheet”.
                    Looks like there would be less ill-post questions in the end of this year, hopefully.

                    On the other hand, I think this time the 2019 Exam 2 Report is “pretty much” the marking scheme itself, except for specific marking allocations and the way to mark the transformation question with wrong letter x instead of t.

                    An extra question to ask you: why do you think MCQ12 in MA094 should have been given a free mark for all students? I think the answer acceptable was A. Some students sent me their mark statement for spesh last year, which indicates the “correct answer” as A.

                    P. N.

                    1. Hi P.N. What exam is MA094? Do you mean Specialist 2019 Exam 2? If so, in Q12 none of the equations can be solved because the given vector resolute is a geometrical impossibility (it is longer than the original vector). The question is defective. Can the equations in Option A actually be solved ….?

                    2. P.N. If you are referring to MCQ12 from last year’s SM Exam 2, that question is completely stuffed: it is stuffed in design, in execution and in practical fact. Anyone suggesting otherwise is being moronic or intellectually corrupt. I understand if the examiners chose A as the “correct” answer but, as is so annoyingly frequent, they are wrong.

        2. Hello Red Five:

          I think the author in charge had already finished this SM report long ago (in the middle of March), but it then becomes mysterious for examination operation units to then publish the document… If I see the updates, I would try to flag it in this post ASAP.

          The setting panel has already done this year’s Spesh paper (originally), but due to the Covid-19, they have to delete the stat questions and fill it up or expand existing questions to a satisfactory level.

          Well, let’s pray for the accuracy, rigor, depths and broadness for the MA093 and MA094 paper this year, as well as MA113 and MA114…in such a special 2020!

          P.N.

          1. PN, I’m also confused by your acronyms. As for the SM report having been completed “long ago”, March is already inexcusable.

            1. JF and Marty,

              Sorry for any confusion I made.

              MA07=Further maths
              MA09=Specialist maths
              MA11=Mathematical Methods

              An extra “3” represents Exam 1, and an extra “4” for Exam 2.

          2. Thanks PN, I still don’t understand why the document hasn’t been published when other reports have been. Sure, some modifications to exams are needed, but I find it quite odd when the other reports are out.

            1. My understanding (based on things said at MAV Conference sessions discussing the exams) was that the Chief Assessor is not on the Exam writing panel. So modification of the 2020 exam should have no bearing on the writing and publishing of the 2019 Examination Report.

              RF, I’ve previously commented (see below) on what I think are the answers to your oddity. I would speculate that an additional reason is debate/concern over how to report on Q12 given the blowtorch applied to it both here (https://mathematicalcrap.com/2020/02/14/witch-35-overly-resolute/) and elsewhere.

              1. JF and Marty,

                Thanks for reminding me the old post.

                Yes, I now see where the mistake is.

                Another pick-up wakes up in my memory, once the MCQ12 in 2019 Exam being mentioned.

                Strangely, every time we have a vector MCQ on Spesh exam, it more or less lacks rigorous ground to hold true, theoretically.

                See 2018, Specialist Maths Exam 2, MCQ12. The same position. Similar flaw.

                The ‘correct’ answer again, is A: vector a is parallel to b….

                Honestly speaking, I’d rather say vector a is in the same direction of b, rather than saying parallel….

                By the way, one more mistake to mention (maybe Marty would be interested in picking it up at some stage), 2019 NHT Exam 2, Question 2, part b: “for what values of k will f_k(x) has no stationary points?”

                The official answer suggested ‘-2<k<0’. However, they ignored the fact that, when k = – 2 or k = 0, there will be one cancellable factor for each case of k, and then, the function f_k(x) will reduce to two rectangular hyperbolae respectively…none of which has any stationary point at all…

                1. Jesus. P.N., is the other 2019 NHT error commonly known? I’ll post on it soon.

                  As for MCQ12 on SM 2018, your suggested answer is more precise but I think “parallel” is ok. There is an underlying issue that “parallel” doesn’t work very well for vectors, as I wrote about in this WitCH.

                  1. Unless incentivised in some way to carefully consider VCAA exam questions, I think many teachers (myself included) take a brief glance at them, see nothing but vanilla and move on. So I think errors will often go unnoticed for some time.

                    And in this particular case the error is in the so-called Report, not the exam, and so it will go unnoticed for even longer because:

                    1) It’s not a report, it’s just a list of answers so there’s no useful insight and so no real point in giving it more than glance (just to check if it’s suffered a case of mistaken identity and is actually a report).

                    2) The report comes out so late that it’s become mostly irrelevant anyway.

                    The troubling aspect of this error is that VCAA has published detailed solutions to this exam and gets the same wrong answer for Q2(b). So the error is clearly not a typo in the report. So in all likelihood the marking scheme has the same wrong answer (and therefore incomplete solution) and therefore every single student who sat that exam has been incorrectly marked.

                    One could say meh it’s just another mathematical error among a laundry list of errors. True, but this latest example of mathematical incompetence by VCAA is very special because there’s empirical evidence showing the thinking that led to the error.

                    Does anyone know of alternative solutions available in the public domain (itute don’t do NHT solutions, unfortunately)?

                1. Well spotted P.N.

                  Regarding those interesting implications: VCAA could almost get away with this by saying that it was a typo. Except for one small thing …. So now there are some different interesting implications ….

      1. Thanks, JF. You’re referring to the expression “reflect in the x-axis” in the answer to Part (e)? For me, the funniest part was the deadpan “There are other solutions.” As, to why it takes them half a year, and counting, to come out with the reports, God only knows.

        I’ll look carefully at the report, and try to put up some new posts in the next few days.

        1. Yes, that’s the expression I’m referring to.

          Indeed, and maybe some of those other solutions involve t. At some stage some quiet revisionism will occur.

          Re: Half a year and counting. Surely the answer, in the ratio of 1 : 1: 1, is because

          they can : they don’t give a flying Philadelphian : they’re a gang of idiots.

          You can say what you like about NESA, but at least they get their reports out for teachers in a timely manner.

    1. Thanks, RF. Yes, to everything (once your correction is included). It’s pretty much what Tau wrote above. I’ll try to update this WitCH soon. (So much crap …).

      1. Sure. I completely agree with what Tau wrote, and would add the question of why matrices ONLY occur in VCAA Methods questions for transformation questions such as these… (which are surely more easily done without matrices at this level???)

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