# WitCH 12: Duplicitous

The following WitCH comes from the VCE 2014 Specialist Exam 1:

The Examiners’ Report indicates that 81%, 48% and 45% of students received full marks for parts (a), (b) and (c), respectively.

## 11 Replies to “WitCH 12: Duplicitous”

1. John says:

In context, having part (b) is dumb. I’d get rid of part(b) and make part (c) (the new part (b)) worth 3 marks, 4 at an absolute stretch.

1. marty says:

Thanks, John. Yes, a weird splitting of the problem.

2. SRK says:

I wonder if the point of having both parts (b) and (c) is to force students to adjust the limits of the definite integral once the substitution is made.

This is not much of a defence of the question, of course. Especially because this sort of thing is routinely assessed on the multiple choice component of exam 2.

2. One does wonder how many students would have scored better for part (c) if the word HENCE was removed…

3. John Friend says:

Getting rid of part (b) and the “Hence” in part (c) would go a long way to getting rid of all the crap here. We can guess what g(x) means (although it’s never defined and is totally irrelevant), and I’m guessing VCAA have a particular “appropriate” substitution in mind out of many that are possible. And we can guess that “appropriate” is linked to “Hence”.

We can indeed wonder how many students would have scored better if we simply had part (a) and a part (c) that began with “Find ….” Another case of mental constipation and verbal diarreah from VCAA.

4. I still think changing “hence” to “hence or otherwise” is a relatively harmless way to improve the question a bit. Sure, it doesn’t eliminate the underlying “follow the recipe and your overlord masters will reward you with a good score” nature of the question, but at least it acknowledges that there *might* be an alternative.

1. John Friend says:

OK, I can live with “Hence or otherwise …” but part (b) has just got to go. I don’t understand why the writer thought including part (b) was such a good idea. It’s just dumb to have it. I’m betting students would have done much better finding the value of the integral had they been left to their own devices.

5. Number 8 says:

Is the word “equivalent” in part (b) bothering anyone or is it just me?

1. John Friend says:

All of part (b) bothers me, so what you’re asking is the equivalent (ha ha) of whether the splinter in my thumb bothers me when I’ve just hit it with a hammer ….

1. marty says:

I agree with both of you.

6. marty says:

Thanks, Everyone. You’ve pretty much gotten to all that bothers me about this question. It’s intrinsically a fine question, but the framing is so vague and clumsy and verbose, it ends up being a mess. I’d suggest also that the mark distribution is pretty weird. I’ll update the post soon.

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