Has it occurred to anyone else that these WitCHes are a blogging Ponzi scheme? As long as we keep posting new WitCHes, no one bugs us about not polishing off the old WitCHes. What the hell; we’ll keep going until someone calls the Blog Cops. And, to continue with the scheme, this WitCH comes from the Cambridge text Specialist Mathematics 1 & 2, in the section titled Linear Diophantine equations. Happy hunting.
This one, with due credit to Bill and Melinda, will be appearing in plenty of right wing snicker-rags in the very near future. It’s really a PoSWW. However, given the previous (and much more important) post, we decided to make it a companion blivit-WitCH. (As well, we’re working on another post on this stuff, in defense of it.)
OK, this is one of those blivit WitCHes. Yeah, sorry, but what are you gonna do? We don’t have the time (or the stomach) to give the stuff below the full-blown critique that it warrants, and there is a stormfront much closer to home. Given the thing has been brought to our attention, however, it also seems an error to not raise it on this blog. And so, here we are.
The question below is from the second 2020 Specialist exam (not online), and was flagged by commenter John Friend in the discussion here. John has spelled out the problems, but the question is bad enough to warrant its own post, and there’s arguably a little more to be said.
This combo WitCH comes courtesy of mystery correspondent, tjrb. They flagged three multiple choice questions from the 2018 Algorithmics exam (here, and examination report here), and we’ve added a fourth. tjrb also remarks, “There are probably a lot more errors in this paper (and the other algorithmics papers), but these were the most strikingly incorrect”.
For Q2, the examination report indicates that 41% of students gave the intended answer of A. By way of explanation, the report then remarks,
“Cobham theorised that problems that are feasibly computable (also known as easy problems) are those that are decidable in polynomial time.”
For Q6, the report indicate that both A (51%) and C (33%) were “accepted”, but is otherwise silent.
The report is silent on Q12 and Q16, except to indicate the intended answers: C (94%) and A (66%), respectively.
The question below is from the first 2020 Specialist exam (not online). It has been discussed in the comments here, and the main issues have been noted, but we’ve decided the question is sufficiently flawed to warrant its own post.