WitCH 140: Honey, Don’t

We’re snowed with grading essays for the Evil Mathologer, and we’re trying very hard to get to a few larger posts. But for now, a quick WitCH. We don’t pay much attention to Foundation Mathematics, which is supposed to be the Easier Than Easy Maths Subject. Commenter Ron, however, emailed us about the following question on VCAA’s sample exam, posted last year. (See also this post.)

You have 90 seconds, and your time starts now.

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VCAA’s Mathematical Flea Circus, Part Two

Yesterday’s post was on the 2023 Methods Exam 1 report (Word, idiots), its foggy focus on trivia and also on the ludicrous non-solution of one particular question. Now, it’s on to Exam 2 Report (Word, idiots), which is what prompted these posts.

Here are the Exam 2 General Comments in their entirety. I have commented elsewhere on a couple aspects (here on Q3(a), here on Q3(e) and here on Q5(b)). I won’t comment further now, except to note that it seems to me to be nothing but fleas. I can detect no sign whatsoever of any underlying host.

This is the first year of the new study design and most students were able to respond effectively to the questions involving the introduced concepts, such as Newton’s method in Questions 3f. and 3g. and the point of inflection in Question 3d.

As the examination papers were scanned, students needed to use a HB or darker pencil or a dark blue or black pen.

Some students had difficulty understanding some of the concepts, such as the difference between average value of a function and average rate of change (Questions 2b. and 2c.). This year two questions involved strictly increasing and strictly decreasing functions. In Question 3e. many students used round brackets instead of square brackets. In Question 5b. either bracket type was appropriate as the maximal domain was not required. Some students did not attempt Question 3a. They appeared to be confused by the limit notation \color{OliveGreen}\boldsymbol{\lim\limits_{x\to -\infty}g(x)}.

Students need to ensure that they show adequate working where a question is worth more than one mark, as communication is important in mathematics. A number of questions could be answered using trial and error in this year’s paper, especially in relation to probability, Questions 4f. and 4g. Drawing a diagram can often be helpful to show the output for some of the trials. Students are allowed to use their technology to find the area between two curves using the bounded area function, but they must show some relevant working if the question is worth more than one mark. Often, questions require that a definite integral is written down, such as in Question 1cii. In Question 4d. students were expected to identify and write down the n and p values for the binomial distribution, not just the answer.

There were a number of transcription errors, and incorrect use of brackets and vinculums, in Questions 1b., 1ci., 1d. and 3ci. Students needed to take more care when reading the output from their technology. For example, some students wrote \color{OliveGreen}\boldsymbol{-\frac{\sqrt7 + 1}{3}} instead of  \color{OliveGreen}\boldsymbol{\frac{-\sqrt7 + 1}{3}} in Question 1b. Others wrote \color{OliveGreen}\boldsymbol{\pm\frac{\sqrt5 - 1}{2}} instead of  \color{OliveGreen}\boldsymbol{\frac{\pm\sqrt5 - 1}{2}} in Question 1ci.

Students need to make sure they give their answers to the required accuracy. In most of Question 1, Questions 3b. and 3h., and Question 4i., exact values were required. In all questions where a numerical answer is required, an exact value must be given unless otherwise specified. A number of students gave approximate answers as their final response to these questions. In Question 3f. some students gave their answers correct to two decimal places when the response required three decimal places.

There were a number of rounding errors, especially in Questions 1ciii., Questions 3d. and 3f., Questions 4a. and 4h., and Question 5ci. Students must make sure they have their technology set to the correct float or take more care when reading and transcribing the output.

Students need to improve their communication with ‘show that’ and transformation questions. There was only one ‘show that’ question this year, Question 2a. Sufficient working out, presented as a set of logical steps with a conclusion, needed to be shown. In Question 5a., the transformation question, the correct wording needed to be used, such as ‘reflect in the y-axis’.

In general, students appeared to have made good use of their technology, for example in finding the equations of tangent lines, finding bounded areas and using graph sliders to get approximate answers to complicated questions. Some students, however, need more practice at interpreting the output from their technology, especially when the technology uses numerical methods to find solutions. In Question 3cii., the tangent line passes through the origin, but some students gave y = 4.255x + 8.14E-10 as their final answer, not appearing to recognise that 8.14E-10 should be zero.

Most students made a good attempt at the probability questions. Some students, however, still misinterpreted the wording. Errors occurred in Questions 4a., b., c. and d.

Students are reminded to read questions carefully before responding and then to reread questions after they have answered them to ensure that they have given the required response. Question 1a. required the answers to be in coordinate form. Question 3ci. required an equation. In Question 3cii. many students only found the value of a and did not continue to find the equation of the tangent.

VCAA’s Mathematical Flea Circus, Part One

To people not involved in Mathematical Methods it is difficult to convey the awfulness of the subject. Even regular readers of this blog, who will be somewhat aware of our million or so posts, cannot properly appreciate Methods’ unrelenting shallowness and pedantry and clunkiness and CASiness. The subject, to the extent there is one, is infested with fleas.

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Estimating Stephen Gniel

Stephen Gniel, of course, was CEO of VCAA while the Deloitte debacle played out, and then during the subsequent 2023 VCE exams battle. Gniel then began his previously arranged secondment, to be Acting CEO of ACARA (also permitting Gniel, it seems, to duck appearing before the Bennett inquiry). It is in the latter role that Gniel appeared (along with Sharon Foster, ACARA’s Executive Director, Curriculum, and Russell Dwyer, ACARA’s Executive Director, Assessment and Reporting) at Senate Estimates on 15 February, in front of the Education and Employment Legislation Committee. I don’t think Gniel had much fun. Continue reading “Estimating Stephen Gniel”

The New Report on the VCE Exams is Out

The report of the VCE exam review conducted by Dr. John Bennett has been handed down. The media release is below and the Executive Summary of the report is here (and in Word). Presumably, there is no intention to release the full report. (23/03/24. And my presumption was wrong. See the update below.) I haven’t yet had a chance to look at anything, and I may update this post later.

UPDATE (20/02/24)

VCAA’s acting CEO, Kylie White, gave a lengthy ABC interview this afternoon. There are also reports in the AgeHerald Sun and EducationHQ.

I’ll leave off writing any detailed thoughts about the report until the dust and my brain have somewhat settled. In brief, while there are significant nits to pick the report is very good on some important recommendations. In particular: employ competent mathematicians; and report in a timely manner. These are not magic wands, but they would be big and important steps.

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A Sum of “Complex” Numbers

We really want to get on to other things, but this needs to be done. Below is pretty much a complete cataloging of Nelson‘s use of the adjective “complex” in the five recent WitCHes (here, here, here, here and here). To be clear, there is tons more wrong, and bad, in the selected excerpts in the WitCHes: the proper WitCH updating, currently scheduled for late 2029, will be long and painful. But the use of “complex” warrants particular attention. It reflects VCAA’s complex madness, and we doubt that it is a coincidence. Continue reading “A Sum of “Complex” Numbers”

WitCH 119: Poly Want a Cracker?

Last one. These are excerpts from the final section of Nelson‘s complex numbers chapter. Similar to the previous WitCHes, I’ve tried to not be manipulative material in selecting the material except, of course, in selecting the worst bits: the worked examples not indicated are standard, and in general the working is tedious but ok; a monotonous but essentially correct proof of the conjugate root theorem is included in the text.

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WitCH 118: The Chaos Factor

I was gonna go with The Sot-Weed Factor, but that was too cute a title, even for me.

We’re now getting to the VCAA-related material, which prompted this whole series. The last two sections of Nelson‘s complex numbers chapter are on factors and roots of polynomials. Below are excerpts on factorisation. (For the sake of interpretation, note that: the factor and remainder theorems are stated reasonably clearly, but of course with no hint of a proof; these two theorems are followed by two standard “worked examples”; the working of all the worked examples is painfully earnest and slow, but is close enough to correct.)

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WitCH 116: Polar Bare

This is our second WitCH on Nelson‘s chapter on complex numbers. As with our first WitCH, we have not excluded any definitions or arguments or explanations from the text that would fill apparent (and actual) gaps in the selected material; the rest of the subchapter consists of routine examples and less problematic (but far from unproblematic) exposition. Continue reading “WitCH 116: Polar Bare”