Okay, quiz should be over.

I would like to comment a bit about the exam,

the number of registrations to that,

and the number of students we see in the quizzes.

So, we're seeing 450 people registered for the exam.

I'm not quite sure, but it's not quite that number of people

who are actually submitting homework.

And we have about 120, sometimes 140 and so on,

and people taking Tuesday quizzes.

I believe that if you think about these homework

and quiz questions and so on,

then I think as computer scientists,

you probably want to think about a course

as kind of a knowledge engineering problem.

We have to engineer that you have all the knowledge

you need for the exam or for me to certify.

And I think of the Tuesday quizzes

and the practice quizzes that go with them

as essentially unit tests for knowledge.

And if you look at the quizzes with an open eye,

and I would advise you to kind of look at them again at some point,

you'll see that the quizzes are designed

to challenge you to think about certain edge cases

or properties of the objects we're talking about

that you may have overlooked.

So one of the questions today dealt, for instance,

with the multiplicity problem we talked about last week,

which is kind of a non-obvious thing,

and it's important that you understand it.

So we're telling one question to exactly tease out of you

whether you have understood this multiplicity thing.

And we're trying to do that with most of the quiz questions.

So I think it's probably, you should probably look at the results.

Here's my version of the results.

Didn't do too terribly well.

That may be a cause of the video of last Wednesday not being,

or having problems of some kind.

I'm in contact with the media centre

of whether we can rescue part of that,

but of course there's the course notes that have all the material.

And there's a good indication that at least some of you

have missed certain things.

So you want to look at the unit tests of knowledge

that are failing for some of you.

Probably not so much the people in the room.

That's typically a good correlation between being here and doing well.

But there's a learning opportunity here.

That's why we have the practice problems on the LAS system.

And that's why we do the tests.

If you think about homework problems,