One FEL Swoop: The Further Error List

This is the home for Further Mathematics exam errors. The guidelines are given on the Methods error post, and there is also a Specialist error post.

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2019, Exam 1 (Here, and report here)

QB6 (added 21/09/20) The solution requires that a Markov process is involved, although this is not stated, either in the question or in the report.

2018 NHT, Exam 1 (Here, and report here)

MCQ4 (added 23/09/20) The question provides a histogram for a continuous distribution (bird beak sizes), and asks for the “closest” of five listed values to the interquartile range. As the examination report almost acknowledges (presumably in time for the grading), this cannot be determined from the histogram; three of the listed values may be closest, depending upon the precise distribution. The report suggests one of these values as the “best” estimate, but does not rely upon this suggestion. See the comments below.

2015 Exam 1 (Here, and report here)

MCQ9 Module 2 (added 30/09/20) The question refers to cutting a wedge of cheese to make a “similar” wedge of cheese, but the new wedge is not (mathematically) similar. The exam report states that the word “similar” was intended “in its everyday sense” but noted the confusion, albeit in a weasely, “who woulda thought?” manner. A second answer was marked correct, although only after a fight over the issue.

Hard SEL: The Specialist Error List

This is the home for Specialist Mathematics exam errors. The guidelines are given on the Methods error post, and there is also a Further error post.

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2006 EXAM 2 (Here, and report here)

MCQ20 (added 24/09/20) The notation F_1, F_2, F_3 refers to the forces in the question being asked, and seemingly also in the diagram for the question, but to the magnitudes of these forces in the suggested answers. The examination report doesn’t acknowledge the error.

MELting Pot: The Methods Error List

We’re not really ready to embark upon this post, but it seems best to get it underway ASAP, and have commenters begin making suggestions.

It seems worthwhile to have all the Mathematical Methods exam errors collected in one place: this is to be the place.*

Our plan is to update this post as commenters point out the exam errors, and so slowly (or quickly) we will compile a comprehensive list.

To be as clear as possible, by “error”, we mean a definite mistake, something more directly wrong than pointlessness or poor wording or stupid modelling. The mistake can be intrinsic to the question, or in the solution as indicated in the examination report; examples of the latter could include an insufficient or incomplete solution, or a solution that goes beyond the curriculum. Minor errors are still errors and will be listed.

With each error, we shall also indicate whether the error is (in our opinion) major or minor, and we’ll indicate whether the examination report acknowledges the error, updating as appropriate. Of course there will be judgment calls, and we’re the boss. But, we’ll happily argue the tosses in the comments.

Get to work!

*) Yes, there are also homes for Specialist Mathematics and Further Mathematics errors.

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2016 EXAM 2 (Here, and report here)

Q3(h), Section B (added 06/10/20)- discussed here. This is the error that convinced us to start this blog. The question concerns a “probability density function”, but with integral unequal to 1. As a consequence, the requested “mean” (part (i)) and “median” (part (ii)) make no definite sense.

There are three natural approaches to defining the “median” for part (ii), leading to three different answers to the requested two decimal places. Initially, the examination report acknowledged the issue, while weasely avoiding direct admission of the fundamental screw-up; answers to the nearest integer were accepted. A subsequent amendment, made over two years later, made the report slightly more honest, although the term “screw-up” still does not appear.

As noted in the comment and update to this post, the “mean” in part (i) is most naturally defined in a manner different to that suggested in the examination report, leading to a different answer. The examination report still fails to acknowledge any issue with part (i).

Q4(c), Section B (added 25/09/20) The solution in the examination report sets up (but doesn’t use) the equation dy/dx = stuff = 0, instead of the correct d/dx(stuff) = 0.

2016 EXAM 1 (Here, and report here)

Q5(b)(i) (added 24/09/20) The solution in the examination report gives the incorrect expression \pm\sqrt{e^x} - 1 in the working, rather than the correct \pm\sqrt{e^x -1}.

2014 EXAM 2 (Here, report here)

MCQ4 (added 21/09/20) – discussed here. The described function need not satisfy any of the suggested conditions, as discussed here. The underlying issue is the notion of “inflection point”, which was (and is) undefined in the syllabus material. The examination report ignores the issue.

2011 EXAM 2 (Here, and report here)

Q4, Section 2 (added 23/09/20) The vertex of the parabola is incorrectly labelled (-1,0), instead of (0,-1). The error is not acknowledged in the examination report.

2011 EXAM 1 (Here, and report here)

Q7(b) (added 23/09/20) The question asks students to “find p“, where \boldsymbol{p} is the probability that a biased coin comes up heads, and where it turns out that \boldsymbol{p^2(4p-3)=0}. The question is fatally ambiguous, since there is no definitive answer to whether \boldsymbol{p=0} is possible for a “biased coin”.

The examination report answer includes both values of \boldsymbol{p}, while also noting “The cancelling out of p was rarely supported; many students incorrectly [sic] assumed that p could not be 0.”  The implication, but not the certainty, is that although 0 was intended as a correct answer, students who left out or excluded 0 could receive full marks IF they explicitly “supported” this exclusion.

This is an archetypal example of the examiners stuffing up, refusing to acknowledge their stuff up, and refusing to attempt any proper repair of their stuff up. Entirely unprofessional and utterly disgraceful.

2010 EXAM 2 (Here, report here)

MCQ17 (added 28/09/20) – discussed here. Same as in the 2014 Exam 2, above: the described function need not satisfy any of the suggested conditions, as discussed here.

2007 EXAM 2 (Here, report here and discussed here)

MCQ12 (added 26/09/20) Same as in the 2014 Exam 2, above: the described function need not satisfy any of the suggested conditions, as discussed here.

PoSWW 12: They is Bach

There’s much we could write about Matthew Bach, who recently gave up teaching and deputying to become a full-time Liberal clown. But, with great restraint, we’ll keep to ourselves the colourful opinions of Bach’s former school colleagues; we’ll ignore Bach’s sophomoric sense of class and his cartoon-American cry for “freedom”; we’ll just let sit there Bach’s memory of “the sense of optimism in Maggie Thatcher’s Britain”.

Yesterday, Bach had an op-ed in the official organ of the Liberal Party (paywalled, thank God). Titled We must raise our grades on teacher quality, Bach’s piece was the predictable mix of obvious truth and poisonous nonsense, promoting the testing of “numeracy” and so forth. One line, however, stood out as a beacon of Bachism:

“But, as in any profession, a small number of teachers is not up to the mark.”

We is thinking that is very, very true.

WitCH 37: A Foolproof Argument

We’re amazed we didn’t know about this one, which was brought to our attention by commenter P.N.. It comes from the 2013 Specialist Mathematics Exam 2: The sole comment on this question in the Examination Report is:

“All students were awarded [the] mark for this question.”

Yep, the question is plain stuffed. We think, however, there is more here than the simple wrongness, which is why we’ve made it a WitCH rather than a PoSWW. Happy hunting.

UPDATE (11/05) Steve C’s comment below has inspired an addition:

Update (20/05/20)

The third greatest issue with the exam question is that it is wrong: none of the available answers is correct. The second greatest issue is that the wrongness is obvious: if z^3 lies in a sector then the natural guess is that z will lie in one of three equally spaced sectors of a third the width, so God knows why the alarm bells weren’t ringing. The greatest issue is that VCAA didn’t have the guts or the basic integrity to fess up: not a single word of responsibility or remorse. Assholes.

Those are the elephants stomping through the room but, as commenters as have noted, there is plenty more awfulness in this question:

  • “Letting” z = a + bi is sloppy, confusing and pointless;
  • The term “quadrant” is undefined;
  • The use of “principal” is unnecessary;
  • “argument” is better thought as the measure of an angle not the angle itself;
  • Given z is a single complex number, “the complete set of values for Arg(z)” will consist of a single number.
  • The grammar isn’t.

The PoSWW Coronavirus Post

We had plans a week ago (seems like a year ago) for a PoSSW coronavirus post. But, God, there is so much stupid right now. Who could possibly keep up?

Here is a dedicated post for coronavirus-related stupidity. Commenters are welcome to point to and give links to specific idiocies, or simply to vent. We’ll update the post with the hyper-stupids. (So, standard Morrison/Trump/Johnson incompetence doesn’t cut it, but unloading a whole fucking boat of sick people most definitely does.)

PoSWW 2 (26/2) Courtesy of occasional commenter Franz, cardiopraxis.de gives us a graph showing what “uncontrolled exponential spreading of the infection” would look like:

PoSWW 3 (27/2) The Guardian royally fucks up their 96pt bold headline:

PoSWW 4 (1/4) Richard Epstein, scientist extraordinaire.

PoSWW 5 (8/4) Peter Navarro, social scientist extraordinaire.

PoSWW 6 (8/4) Media Watch hammers Australia’s right wing loons. (Andrew Bolt wins the Loon Gold Medal at 8:00).

PoSWW 7 (8/4) The leader of Wisconsin’s psychopathic Republicans tries to convince voters that “you are incredibly safe to go out”:

PoSWW 8 (15/4) ScoMoFo in a radio interview:

“The president of the United States, Donald Trump, announced that he would suspend funding for the WHO while they investigate whether it’s handled the COVID crisis properly. Good move, bad move?”

“Look, I sympathise with his criticisms, …”

Wrong. The answer is “Bad move”, you useless, greasy dickwit.

PoSWW 9 (21/4) Uhlmann or IPA or Creighton or Lovick or Goward or Farrelly.

PoSWW 10 (21/4) The Wall Street Journal on a problem we can all understand:

PoSWW 11 (21/4) ScoMoFo indicates how much he appreciates teachers.

PoSWW 12 (21/4) Trump supporters demonstrating (their level of intelligence):

PoSWW 13 (1/5) Way to send the message, Ponce:

PoSWW 14 (11/5) The DCMO compares Cook to a virus. And what kind of third rate whiny little shits would pretend to give a fuck? These assholes. And this born to rule batfucker. And of course this racist, Ruby-Princess-Docking, fascist fuckwit.

Just how dumb do you have to be to buy the garbage that these motherfuckers are selling?

PoSWW 15 (11/5) Melbourne’s best and brightest, spurred on by Batfucker Smith, think they’re “spreading the word”:

PoSWW 16 (11/5) God help us:

PoSWW 17 (18/5) French muslims can simultaneously be fined for covering and not covering their faces.

Gambling with Coronavirus

Australia’s casinos are still open for business, and no one seems to see anything wrong with that. Our glorious leaders are out of their fucking minds.

UPDATE (19/03/20)

A number of prominent public Health Professionals have written an open letter to Australia’s health ministers and (the stunningly appropriately titled) gambling ministers. The letter is written in a predictably calm, professional and diplomatic manner, but we’ll translate: you people who signed off to keep pokies venues open are out of your fucking minds.

PoSWW 11: Pinpoint Inaccuracy

This one comes courtesy of Christian, an occasional commenter and professional nitpicker (for which we are very grateful). It is a question from a 2016 Abitur (final year) exam for the German state of Hesse. (We know little of how the Abitur system works, and how this question may fit in. In particular, it is not clear whether the question above is a statewide exam question, or whether it is more localised.)

Christian has translated the question as follows:

A specialty store conducts an ad campaign for a particular smartphone. The daily sales numbers are approximately described by the function g with \color{blue}\boldsymbol{g(t) = 30\cdot t\cdot e^{-0.1t}}, where t denotes the time in days counted from the beginning of the campaign, and g(t) is the number of sold smartphones per day. Compute the point in time when the most smartphones (per day) are sold, and determine the approximate number of sold devices on that day.