Secret Specialist Business: Exam 2 Discussion

This is our post for teachers and students to discuss Specialist Exam 2 (not online). There are also posts for Methods Exam 1, Methods Exam 2 and Specialist Exam 1.

UPDATE (11/09/21) The examination report is here (Word-VCAA-stupid). Corresponding updates, are included with the associated question, in green, and see also here, here and here.

UPDATE (31/12/20) The exam is now online.

UPDATE (03/12/2020)

We’ve now gone through the multiple choice component of the exam, and we’ve read the comments below. In brief, and ignoring the screw-ups, most of the questions seemed good, and a number of questions were hard (which is good). We haven’t thought much about the extent to which the questions are trivialised by CAS/Mathematica, although this is of course extremely important; the comments below on this aspect are well worth a careful read.

Here are our question-by-question thoughts:

MCQ1. A decent and non-trivial stationary point question. A pretty mean way to begin.

MCQ2. A contrived and tricky range of function question. A very mean way to continue.

(11/09/21) 42% correct, which is no surprise. The problem was to find the range of g(x) = |bcos-1x -a|, given a, b > 0, and (weirdly) a < bπ/2. The note in the examination report suggests to “Use transformations on g …”, which is incomprehensible. Simplest is to note the extreme values of cos-1x are 0 and π, and then note that we pass through 0 along the way.

MCQ3. A rather weird piecewise constant acceleration question.

MCQ4. A good and not so easy composition of functions question.

MCQ5. Intrinsically a routine and good complex algebra question, but the presentation is a mess. The notation \boldsymbol{z = a + bi} is introduced, but then plays no role; indeed, the question would have been vastly improved by having the offered answers expressed in terms of \boldsymbol{a} and \boldsymbol{b}. Requiring some extra algebraic manipulation to obtain the correct answer is needless, and a little contrived. (11/09/21) Plus, the gratuitous and stupid use of “equivalence”.

MCQ6. A very easy complex factorisation question.

MCQ7. Ugh! See here.

(11/09/21) 26% correct, solely down to the question being tricked-up garbage. The problem was to choose the partial fraction form of 1/ax(x2 + b), where b < 0. What kind of asshole does that? Plus, as discussed here, the non-appearance of the factor 1/a in the correct answer is absurd. 

MCQ8. A nice complex algebra question.

MCQ9. Complete nonsense, as flagged by commenter Red Five, below. See here.

(11/09/21) 35%, which is to be expected on a question that is meaningless crap. VCAA has absolutely no excuse for including such garbage on an exam.

MCQ10. A routine tank mixture problem.

MCQ11. A screw-up, and perhaps a semi-deliberate one, as flagged by commenter John Friend, below. See here.

MCQ12. A straight-forward but nice Euler’s method problem.

MCQ13. A standard linear dependence problem. As noted by commenter John Friend, the problem is trivial with 3 x 3 determinants, which is not on the syllabus but which is commonly taught for this very purpose.

MCQ14. A straight-forward force component question.

MCQ15. A nice parametrised curve question.

(11/09/21) 38%, which is ridiculous. The question is completely routine.

MCQ16. A nice dot product and double angle formula question.

MCQ17. A straight-forward acceleration as a function of distance question.

(11/09/21) 58%, on a trivial question. It can be done in one’s head in 5 seconds.

MCQ18. A straight-forward but nice string tension question.

MCQ19. A cricket ball with a mass of 0.02 kg? Otherwise, a nice change of momentum question.

MCQ20. A straight-forward but nice force and acceleration question.

UPDATE (04/12/2020)

We’ve now gone through Section B (extended question) of the exam, and we’ve read the comments below. There do not appear to be any significant screw-ups, but most of it is pretty poor. In the main, the questions are aimless and badly written, with CAS washing away the potentially good effect of any decent content. Nothing is quite a WitCH or PoSWW, but almost everything is close.

Here are our question-by-question thoughts:

Q1. A strikingly aimless parametrised motion question. Seriously, who gives a shit about any of it? Part (b)(i) asks for dy/dx as a function of t, to “hence” obtain the equation of the tangent at t = π, when it is more natural and simpler to first evaluate dy/dt and dx/dt at π. Then, (b)(ii) asks for the velocity at π, for which you need … This is stupid with a capital stupid.

(11/09/21) In an ever-changing world, there is something reassuring about the clockwork predictability of VCAA’s pedants whining about a “missing dt” in an integral.

Q2. An OK complex geometry question, which begins thusly:

Two complex numbers, u and v are defined as \boldsymbol{u = -2 -i} and \boldsymbol{v = -4 -3i}.

Jesus. What’s wrong with “Let \boldsymbol{u = -2 -i} and \boldsymbol{v = -4 -3i}“? The symbols \boldsymbol{u} and \boldsymbol{v} are pretty crappy choices for fixed complex numbers, and the later choice of \boldsymbol{z_c} for the centre of a circle is really crappy. Part (d), finding the centre and radius of this circle, would be a nice question in a CAS-free world.

(11/09/21) Part (c) was a vaguely worded 1-pointer, asking for the “geometric interpretation” of the graph |z – u| = |z-v| (with u and v fixed); but, at least the examination report indicates that “A variety of reasonable responses were accepted”. Similarly, Part (d)(ii) is a 1-pointer required students to graph an open ray, whose endpoint had already been plotted; the examination report does not indicate fussing about the endpoint. There was nasty fussing, however, in the very next question. Part (d)(i) casually asks students to “Write down” the equation of the function Arg(z-u) = π/4 in cartesian form, with no emphasis in the original. And, of course, 3/4 of students scored 0/1:

While a high proportion of students gave the correct rule, many did not fully describe the function as they did not include the domain.

Anybody want to “fully describe” this dickishness? And, if we’re going to play pedant games, Part (e) asks students to find a and b, but the solution in the report instead uses m and n. Of course. Because it’s in the nature of these pig-ignorant bullies to fuss endlessly over trivia in student work, and to fuss zero-ly over the quality and accuracy of their own writing. 

Q3. The best question, graphing \boldsymbol{f(x) = x^2e^{-x}} and then finding the number of inflection points of \boldsymbol{g(x) = x^ne^{-x}} for \boldsymbol{n\in\mathbb Z}. Much of the goodness is killed by CAS. It is not entirely clear what is meant by “asymptotes” in part (b). (See the discussion here.)

(11/09/21) As commenters have noted, the final Part (e) was an insane amount of work for 2 marks, and the grading was consequently insane to match. Previous parts of the question, which were “handled well” (by the machines), involved calculating g”(x) and then solving g”(x) = 0. In effect – and summarised incomprehensibly in the examination report – students had worked out that there were no solutions of g”(x) = 0 for n < 0, and for nonnegative n, 

    \[\color{OliveGreen}\boldsymbol{ g''(x) = \left\{\aligned &e^{-x} \qquad &&n=0\\ &(x-2)e^{-x} \qquad &&n=1 \\&x^{n-2}\left(x-n-\sqrt{n}\right)\left(x-n+\sqrt{n}\right)e^{-x} \qquad &&n>1\endaligned\right.}\]

Part (e) then required students to fill in a table, indicating for each n whether g(x) had 0, 1, 2 or 3 inflection points. Even assuming that students had suitably organised their previous work, and even given that apparently no working on Part (e) was required, that’s a hell of a lot for 2 marks. And, with a catch. The xn factor means that, for n >1, there is an inflection point at x = 0 if n is odd, but not if n is even. Then, presumably 1 mark out of 2 was deducted for a single error. (And, two marks deducted for two errors?) A final average of 0.2/2 was the inevitable result. Utter madness.

Q4. Another parametrised motion question, this one involving a pilot seemingly unaware of the third dimension. Pointless and boring CAS nonsense.

Q5. An absolute mess of a dynamics question. The diagram is shoddy. The appropriate range of the frictional parameter \boldsymbol{k} should be given or determined before asking students to compute a Fantasyland acceleration. Part (e), which feels like an afterthought, involves a jarring and needless switch from the algebraic to numeric, with a specific velocity and implausible force plucked from thin air.

56 Replies to “Secret Specialist Business: Exam 2 Discussion”

  1. It was good to see a few *new* multiple choice questions that didn’t reward blatant button-pushing. Of particular note, I thought Q4, 5 and 8 were pretty nice (come on – tell me why I’m wrong…)

    Q9 though… I think I know what the intended answer was (B) but with the absence of any reference to a differential equation, I am a bit lost as to exactly what “curve” the question is actually referring to.

    It seemed a bit… odd. But I do not know enough about differential equations to know if this is an error or not (and I get the feeling some regular readers will soon be able to assist)

    1. I agree, RF. And I also liked Section A Q2. But Q8 was trivial with button pushing: Just let x = 2 and y = 1, say, calculate the powers and then choose the consistent option.

      Re: Q9. A simple diagram facilitates getting the DE \displaystyle \frac{dy}{dx} = \frac{y}{x-y}. Then you can either button push to get the slope field and choose the compatible option (trivial with Mathematica using StreamPlot), or you can use your brain and eliminate all the wrong options in the following way:

      \displaystyle y = 0 \implies \frac{dy}{dx} = 0 therefore only options B, C and E are viable.

      \displaystyle x = 0 and \displaystyle y > 0 \implies \frac{dy}{dx} = -1 therefore only option B remains.

      A couple of superficial observations (I haven’t had a chance to sit down and do the exam in detail):

      I disliked Q13 (“The vectors … will be linearly dependent when the value of \lambda is”) because well-taught students can just set the determinant of an appropriate 3×3 matrix equal to zero – absolutely no understanding is required.

      I thought Section B was *mostly harmless*. It’s been a long time between drinks when students last had to state the geometrical interpretation (Q2 (c)) of |z - u| = |z - v| as ‘the line that is the perpendicular bisector of the line segment joining z = u and z = v.’

      I thought Q3 was very interesting – parts (d) and (e) are clearly intended to ‘force’ teachers to include a generalisation in their SACs …

      1. I found Q8 to be pretty simple without choosing specific values, but yes, in this case it would be an easy way to get a correct answer.

        The geometry of the Argand diagram has been so much about circles and rays lately that seeing a perpendicular bisector was nice, although all my students will know this ad nauseum from Year 11.

        Overall, I felt Part B was a lot easier than previous years. Part of me wonders why (given what happened in Methods)

        Still not convinced MCQ9 actually works as a question, mainly because I’m not convinced that “a curve” and a solution to a DE have to be the same thing just because a slope field is given. Don’t have the mathematical knowledge to know where to begin to understand if the question is valid or not – hence I come to Marty’s blog!

      2. I should add that Q11 is an improper integral (I wonder if the exam setting panel even understand what these are since they keep appearing) but no calculation is required so I suppose it can go through to the wicket keeper.

        1. And a lucky thing no calculation was required. The integral doesn’t converge! Maybe that was deliberate so that students couldn’t compute the value with a CAS and then compare with the value from the options … (Still, it’s a cheap trick). Here is the question:

          Question 11
          With a suitable substitution \displaystyle \int_{\frac{\pi}{4}}^{\frac{\pi}{3}} \frac{\sec^2{x}}{\sec^2{x} - 3 \tan{x} + 1} dx can be expressed as

      3. I should add that Q11 is an improper integral (I wonder if the exam setting panel even understand what these are since they keep appearing) but no calculation is required so I suppose it can go through to the wicket keeper …

      4. Thanks, JF. Q2(c) puzzled me, because I thought of the geometric interpretation as the natural way to get the equation of the line in 2(a). Isn’t that typically taught?

        Definitely B3 is the nicest question on the exam, although, as always, it’d be infinitely better without CAS. I’m also assuming the final table of inflection points requires only answers; if some explicit justification is required, that’s a hell of a lot of work for 2 marks.

        1. Hi Marty.

          Re: Q2(c). Yes, it *is* typically taught AFAIK. And many students will have chosen to answer (a) using this method. So I agree that part (c) is puzzling – it will be interesting to see the performance of the cohort in the Examination Report.

          Re: Q3. Well, 7/10 of the marks are Maths Methods marks so I don’t think it’s much chop as a *Specialist* Maths question. And most of those 7 marks are trivialised by the CAS. I can’t see any requirement for showing change in concavity so even the 3/10 Specialist-specific marks are weak as piss.

          I think (e)(ii) is intended to push the not-so-secret agenda of getting teachers to include generalisations in their SACs. It wouldn’t be the first time VCAA has tried to ‘nudge’ teachers through exam questions. I’d guess 1/2 a mark for each answer – justification is clearly NOT required because it simply says “… stating the value(s) of n”. Plus there are no writing lines, only working space. Now, if it had said “… *finding* the values of n” …

          So sorry, Marty. I think the question is a shit Specialist question. If it was on a Methods Exam 1 and reference to points of inflection deleted, it would be a nice question.

          1. Yes, that’s a very good point. I still think it’s a nice question (in a CAS-free world), but it’s a nice Methods question, not a Specialist question.

              1. Yes, it tells me that barely half the state either:

                (a) do not understand the geometrical interpretation, or
                (b) have not been taught the geometrical interpretation, or
                (c) could not state to VCAA’s satisfaction the geometrical interpretation.

                Since it’s easy to understand and the statement is simple, I’m guessing that most of the students who got zero fall into category (b) (which I find astounding).

                I could make much better sense of the mean result if students had to state a geometrical interpretation of the graph of something concrete like \displaystyle |z + i| = |z - 1| (because careless mistakes then play a larger part) …

                It’s very unlikely to appear on this year’s exam, but if it did I’d bet the average mark would be closer to 0.9 …

                1. It can’t be that they wanted something like “equidistant” rather than “perpendicular bisector”, can it?

                  1. You would hope not, particularly given that (most recently) the 2015 Exam 2 Report refers to it as “the perpendicular bisector …” in Q2(a)(ii). Then again, consistency is not a VCAA strong suit.

                    But wait a moment … maybe they wanted the word line interval and not line segment …? (They use interval in that Report). I guess we’ll find out when the Report comes out some time in 2022 (if we’re lucky). When it comes to the mathematically holier than thou VCAA goons who decide this stuff, it’s anyone’s guess.

                    1. One should never be surprised if VCAA goonishness is involved. But, in this instance I suspect that students’ weak geometric sense of complex numbers is the problem. And, even before that, the sense of |z – w| as distance. I don’t know why, but this easy topic has always seemed weak in the Specialist students I’ve quizzed.

    2. Re: Q4

      If we’re going by the maximal capability of what any of the allowed CAS calculators can do (i.e Mathematica) then unfortunately, Mathematica can completely steamroll the question. The code below does just that:
      FullSimplify[f[g[x]], 0 < x < \[Pi]/2] // TrigReduce
      FunctionRange[{1/2 Sin[2 x], 0 < x < \[Pi]/2}, x, y]
      If we're talking about the TI-nspire, it will also simplify the function (albeit with a mod sign) and all that's left is to determine the range of the function, which is more or less trivial. Nothing really tested if any student just threw the expression into their CAS.

      Re: Q5
      I don't really have any issues here, it's a decent way of testing properties of complex numbers.

      Re: Q8
      Just a question here, would it be frowned upon if instead of manipulating the expression into one that relates to the original expression, a student chose to plug in arbitrary values of x and y?

      Re: Q9
      What JF said, although personally using StreamPlot requires some good eyesight… In case the derivation was not so obvious, you would do it like so:

          \[y-y_0 = \frac{dy}{dx} (x-x_0)\]

      Substitute y=0 then rearrange for x as follows:

          \[\frac{-y_0}{\frac{dy}{dx}} +x_0 = x\]

      Then finally equate that for the value at that point:

          \[\frac{-y_0}{\frac{dy}{dx}} +x_0 = y_0\]

      Finally, rearrange for \frac{dy}{dx} and you're ready to squint your eyes at 5 different options. I'm not really certain on the validity of the question myself however….

      1. Hey Sai,

        Q4 for MCQ would’ve been a nice composite functions question if it wasn’t trivialised by Mathematica/CAS. I solved the question in reading time (it caught my interest!) whereas my friends just brute forced it on the TI Inspire, LOL!

        I was surprised that the geometry of circles didn’t come up this time for Q5. I felt that this exam was very physics themed and would be nicer with more creative geometry.

    3. Please allow me to reiterate my objection to multiple choice questions. The purpose of an examination is to assess where students are up to in learning about the subject. Suppose that my answer to a multiple choice question is (C). What does that tell you about my learning?

      If (C) is the correct answer, can you infer that I understand what is being tested? Not really – I might have guessed, or I might have got to (C) because I eliminated the alternatives but have no idea why (C) was correct, or I might have meant (B) but accidentally wrote (C). In any case, my score is 1.

      If (C) is not the correct answer, can you infer that I don’t understand what is being tested? Not really – perhaps I made a mistake in a calculation, or I knew the correct answer and accidentally wrote (C). In any case, my score is zero.

      Now the response of experts in assessment is that you don’t assess a student’s learning about a topic by a single MC question. You should ask several MC questions on the same topic to get an understanding of the student’s learning on the topic. This process is called triangulation. But in an examination, one does not ask several questions on the same topic.

      What does (C) tell us? Thus endeth the lesson.

      1. TM, as far as the VCAA exams are concerned, I am in complete agreement with you. I hate them on the VCAA exam – they are purely a stupid cost saving measure. I’d like to see them wiped from the face of the Earth and get either a shorter Exam 2 (90 minutes) or two extra extended-response questions.

    4. Thanks, RF. I’m just going through the exam now. I pretty much agree, although MCQ5 annoyed me in the way it was presented. MCQ9 is, as you suggest, ridiculous. I’ll post on it soon.

      1. The complex numbers question where the argument of u is pie on 4 and it asked for the equation of the line. I had y=x+1 and stated the correct domain but it wasn’t in the full like function format

  2. I’m curious how Section B Question 4d (asking if the drone makes contact with the aeroplane, giving reasons) will be marked – in particular, what will count as sufficient evidence.

    I imagine many students will just use CAS to solve when the horizontal components are equal and then to solve when the vertical components are equal; CAS gives approximate solutions only, but there is no common solution, so no collision. But since CAS only gives approximate solutions, will students be required to give evidence that there aren’t OTHER solutions that perhaps the CAS is not finding? For instance, perhaps by sketching appropriate graphs and showing the locations of zeroes.

    1. Good question. Who knows what pinheaded reasons will be required. However if common sense prevails (a huge assumption), then

      “use CAS to solve when the horizontal components are equal and then to solve when the vertical components are equal; CAS gives approximate solutions only, but there is no common solution, so no collision”

      will be sufficient to get the 3 marks:
      1 mark for both equations,
      1 mark for the approximate solutions to each equation,
      1 mark for a conclusion based on those solutions.
      And I suspect explicit inclusion of the domain 0 leq t leq 40 somewhere will be required.

      A CAS calculator does not warn that other solutions might be possible. Mathematica gives all of them (this is certainly expected from Mathematica and assesors won’t know who’s using Mathematica …)

      The plot of y = 450 – 150 Sin[pi*t/6] and y = 30*t for 0 leq t leq 40 is interesting – there is *nearly* a second solution which is very close to one of the solutions to 400 – 200 Cos[pi*t/6] = -t^2 + 40*t ….

    2. SRK, what is the alternative to what you are suggesting? There’s no way to get exact solutions to the two equations.

      1. I generally get a bit nervous when my TI just gives me approximate solutions (ie. perhaps it is missing some, although I know that it is supposed to give an error / warning message in these cases), so for this question I used the CAS to display the graphs of x_D(t) - x_A(t) and y_D(t) - y_A(t) and roughly sketched those on the page, along with approximate location of zeroes, just to confirm that there’s none in common.

      1. JF what about parts of question 5 where they ask for the time and distance in terms of k?? Are answers which are in terms of g acceptable or do we have to further simplify it??

        1. Roronoazoro, it’s an excellent question. (I means yours is an excellent question. The exam question is woeful.)

          Given (b)(i) leaves \boldsymbol{g} as \boldsymbol{g}, I think the natural interpretation of (c) and (d) is to do the same. I don’t see how substituting \boldsymbol{g = 9.8} could be regarded as incorrect, but who knows with these clowns?) It is all muddied, however, by the idiotic part (e), which of course requires using \boldsymbol{g = 9.8}.

  3. Question 2 (11 marks)

    Two complex numbers, \displaystyle u and \displaystyle v, are defined as u = -2 - i and v = -4 - 3i.

    b. Plot the points that represent \displaystyle u and \displaystyle v … on the Argand diagram below. (2 marks)

    d. i. Sketch the ray given by \displaystyle \text{Arg}(z - u) = \frac{\pi}{4} on the Argand diagram in part b. (1 mark)

    Hands up those who see the conundrum here. (If \displaystyle u was a cat it would surely be called Schrodinger).

    Incidentally, surely the preamble would have been much better as “Let two complex numbers u = -2 - i and v = -4 - 3i.” (But VCAA loves its bloated sentences).

    1. JF what made that part d. i. so annoying was that the ray plays absolutely no role in the rest of the question – it could just as well have been Arg(z – i) = pi/4 without any loss.

      I read part d. ii. – which strongly suggests that students need to write down the domain of the line – as a tacit admission that it’ll be difficult to tell from responses to d. i. if students have drawn the graph correctly, so hopefully this means students won’t be penalised for an ambiguous graph at the endpoint.

      1. SRK, rereading the question, I think you’re probably correct. The wording “Write down the function” is reasonably read to require a domain as well. The casual “write down”, however, subliminally suggests otherwise. I’m guessing that the domain is required and that many students will not include the domain, costing them, presumably, 100% of the marks on this question.

        Yes, the non sequiturishness of the question is also notable, although pretty much the whole exam is one big non sequitur. I wonder if it is intended as a semi-hint to part (e), which can nicely be done by hand. But probably not: why think when you can CAS?

    2. JF, apart from part (d), I really liked this question because it was refreshingly different to the way loci of the complex plane have been examined in recent years (what with the areas of sectors and over-reliance on rays and circles).

      Sure, it isn’t anything a middling Specialist Unit 2 student couldn’t handle (but that could be said for any of the non-calculus parts to a certain extent). I just felt this was actually a decent question…

      …until part (d).

    3. JF, the preamble is indeed awful.

      My hand is nervously raised for (d)(i). Is your concern that \boldsymbol{u} is sometimes used as the real part of \boldsymbol{z}? No question that \boldsymbol{u} is a crappy choice for a fixed complex number, and the wording is pretty sloppy.

      1. Marty, think about how you would plot the point u in part (b). Now think about how you would sketch the ray in part (d)(i) – in particular, what has to happen at the terminus …

        1. Oh, the problem being that \boldsymbol{u} has already been marked on the graph, but \boldsymbol{u} is not part of the ray that is now being drawn?

          1. Bingo! How dumb is that.

            And none of the vettors spotted this. Including the blind reviewer who is meant to do the exam exactly as a student would. Keystone cops stuff.

            1. Yeah, I see. Pretty dumb. Not that hard to make clear in a diagram, and I imagine the examiners will have no choice but to ignore the endpoint of the ray. But gratuitous confusion in a gratuitous question.

              1. Not pretty dumb. Ugly dumb. Dumbness that makes the question a mess. The assessors meeting would have been interesting. It gets back to SRK’s astute insight:

                “I read part d. ii. – which strongly suggests that students need to write down the domain of the line – as a tacit admission that it’ll be difficult to tell from responses to d. i. if students have drawn the graph correctly, so hopefully this means students won’t be penalised for an ambiguous graph at the endpoint.”

  4. So what do you reckon I’d get if I score 37/40 in exam 1 and 74-76/80 in exam 2.
    This is based on me being ranked 1 in a cohort with a sac average of 93%.

  5. Re: Q3.

    And the rest of the goodness was killed by having to answer part (e)(ii) in 3 minutes (2 marks at 1.5 minutes per mark). Even forgoing a proper analysis (not that the question is asking for a proper analysis, just some lucky guesses) and simply relying on some pictures and some solutions to a general equation, there’s no chance of getting correct answers in 3 minutes. VCAA stupidity at its finest. I’d love to see the dipshit who thought this was a good idea answer one of *my* 2 mark questions in 3 minutes (or even 6 minutes).

    Except for part (e)(ii), NONE of Q3 is Specialist – it’s Methods (even part (b) is Methods in my view). So get rid of all the Methods bullshit prior to (e)(ii), just have one or two key parts that lead up to (e)(ii), and make (e)(ii) worth 5 marks (= 8 minutes. Still not ideal but at least students can attempt a proper analysis).

    No surprise that the average mark for (e)(ii) was 0.05 marks out of a possible 2 marks. Yes, 0.05.

    The only reason this question was on the exam was to ‘nudge’ teachers to include this sort of stuff on their SACs (if it’s on the exam, it will get put on every teachers SAC). Pure VCAA manipulation of teachers at the expense of students.

    1. Thanks, JF. The exam report isn’t out, so I’m interpreting this as information from a little birdie? Do we assume (or know) that students just looked at (e)(ii), said “screw this” and moved on? Or, is it that many students did a lot correct, but still had 2/2 marks deducted?

      Either way, if the average score on a question is 0.05/2 then someone seriously crewed up.

      1. The question did not ask for working, simply to fill out a table with 4 answers (my guess is 1/2 mark per answer which then got rounded down). So at best students got 1 answer correct.

        There was no little birdie in this case: The data for the 2020 maths exams (mean mark per question etc.) is currently available to all schools via the VASS. Which brings us to the following interesting question:

        The data for the maths exams is currently available to schools via the VASS so obviously it’s available for the Examination Reports. And we know that assessors who present at the very lucrative MAV ‘Meet the Assessor’ workshops (15 March – 24 March) simply regurgitate the maths examination reports. So it seems to me that the Reports should be available. So why haven’t the Reports been published??

        Are we too cynical in thinking that VCAA (or more specifically the Mathematics Unit of VCAA) has a ‘special arrangement’ with the MAV so that mathematics examination reports will not get published until well after the MAV ‘Meet the Assessor’ workshops have finished?

        It’s hard to imagine these MAV workshops conning teachers into attending and hence being so lucrative if the Examination Reports were available before these workshops ran. I’ve noticed that the 2020 Examination Reports for many other VCE subjects are now available (English – arguably the most complex report to write was available a couple of weeks ago). To paraphrase Shakespeare – “Something is rotten in the state of VCAA.”

        1. Thanks, JF. So, a reasonable guess is that 19/20 students got 0 or 1 of the four 4 answers correct. assuming the students cheated and assumed (e)(i0 was conclusive etc, was the question really that hard.

          As for why the exam reports are not out, I doubt that it’s a conspiracy. Indifference and incompetence is sufficient explanation.

      2. Marty, I think the question was hard if not impossible to do in 3 minutes. The question is a disgrace in this context. It encourages blindly solving equations and groping at graphs without any substantial mathematical analysis. It discourages careful mathematical thinking in a way that I’ve rarely seen. One could argue it requires at least 30 minutes of careful analysis. And VCAA have the gall to bang on with its mathematical thinking jibber jabber. I will post my analysis of the question in the next few days (it would be very interesting to see the MAV solution for this question …)

        *URGENT*: On the subject of jibber jabber, the deadline for feedback on the draft Stupid Design is 9 March.

        Re: Reports. Yes, I know you favour the ‘when in doubt, assume incompetence and laziness’ theory. Even so, I think that still leaves plenty of room for a conspiracy theory (and in fact makes a conspiracy theory even more plausible).

        1. It’s possible. If a) the people who write the reports for VCAA are the same people who do the MAV’s “Meet the Assessors” events; b) these people are paid by the MAV for the assessor events; c) the reports are not out a decent time before the assessor events, then I think these people have questions to answer.

          I think it’s a separate reality that these assessor events will be successful anyway, even if the reports have been released. Teachers imagine they will get more practical advice than I think they do. As well, it’s an easy and brainless way to clock up some PD. (Teachers are also under the illusion that they have to do a mountain of formal PD to get their yearly accreditation from VIT. This is false.)

          1. I don’t know how the VIT maintains this illusion although I think schools and teachers play a large part (teachers are their own worst enemy). Teachers don’t realise that as long as you keep a diary, you can include things like meetings, assessment writing and vetting, mentoring, internal PD, professional reading, fiddling around with things like Mathematica, READING STUDY DESIGN DRAFTS AND SUBMITTING FEEDBACK etc. Education PD is a huge gravy train and a gigantic con job that depends on this ignorance. And the VIT fosters this. But the VIT can’t even do its core job properly – re-registration of teachers. It’s currently giving mealy-mouthed excuses why it hasn’t processed teacher re-registrations submitted 6 months ago. It staggers me that a total disgrace like the VIT has so much power. Or that the joke of an AEU can let them get away with it. Teachers had to push on in 2020, but the VIT was allowed to just sit on its fat arse and contemplate its navel. Our \textdollar 98 annual fee in action.

            As for the practical advice that teachers imagine they get from ‘meet the assessor’ workshops, that’s one of the biggest con jobs in education. The workshops promise so much and deliver so little. And yet the rubes keep attending in large numbers. This way to the egress. Maybe if schools re-directed their PD budget towards things like teachers aids and tutors etc. student education might improve. This gigantic con job would surely end if teachers had to pay out of their own pocket.

            The people who do work for the MAV are often the same people who do work for the VCAA – it’s a very incestuous relationship. The other day just for laughs I looked up who the assessors were that all the rubes will be meeting. And laughed.

            Anyway, I wonder if the MAV solutions (written by these assessors) to Q3(e)(ii) look anything like what I’ve attached (copyright reserved 2021 by John (No) Friend (of VCAA). Warning: Contains Mathematica code that may offend some viewers). Yep, 3 minutes of thinking and writing was all it needed (I’m being sarcastic). I think many students might have correctly said (guessed) no points of inflection when n \leq 0 but that only a very, very small minority then gave another correct answer like 1 PI when n = 1. So most students will get rounded down to zero, and maybe 100-200 students out of 4000 or so students got 1 mark. I’d love to know if there was any student who got 2 marks …

            There’s been a recent trend of VCAA questions worth 1 or 2 marks that require significant careful analysis but discourage students from doing so (the 2019 Methods Exam 1 Q9 (f) immediately comes to mind). In fact, encourage students to do the exact opposite – forget careful mathematical analysis, take a wild guess and hope for the best.

            2020sm-exam 2-Q3eii-The Friend Solution

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