OCR (not MEI) S3 - 20/01/2012

Anyone taking this? I've self-taught and it's going to clash with C3 and AFAIK I'm the only person in my school doing it, so the 20th's going to be interesting.

How's the formula memorising going? There's so much!

I'm taking it too; I'm trying to rely as much on the formula booklet as I can but I've realised I'll have to memorise the formulae for the latter parts of chapter 4 . Ah well, hopefully it'll go well...

OOH FINALLY, SOMEONE!!! I've made revision cards for all of the formulae. Also, if you can read it (huge image):
http://i44.tinypic.com/16m7ned.jpg
There's so much hypothesis testing and confidence interval stuff to remember! And there's not much in the formula book.

Anything you're not great on?

Wow! That is....keen .

I think Ch2 on Continous Random Variables? I always seems to screw up the CDFs and PDFs. Although, I am resitting this (I took it last June) along with FP1/2/3 - and have focused mainly on the pure modules (a combination of obsession and I know I'll have to be familiar with the pure side of maths at university...not so much S3).

I'll start a past paper tomorrow and see how it goes...and then start panicking. You seem really prepared for this! You taking any other modules in January?

I love pure maths <3

Ah, the Var(aX+b)= either a(Var(X)) or a²(Var(X)) depending on whether it's a lots of observation or one observation multiplied by a? Apparently that's a bit that some people don't like. Or do you mean Ch1 where there's all of the f(x) -> F(x) -> G(y)->g(y)?

I've done a couple of papers, the first with the formulae in front of me and the second without it. I'm on an A but I'm aiming for A*.

I've posted threads for all the ones I'm doing: M2 on the 13th, S2 on the 17th, C3 and S3 on the 20th, D1 on the 23rd and D2 on the 25th.

I'm worried that they'll put on some integration/differentiation that I haven't learnt yet, I had that issue with my first go at S2. They made me integrate 1/x and I hadn't done that yet. I've already had to look up the integration/differentiation of sin(ax) and cos(ax) for S3.

No I mean f(x) -&gt; F(x) -&gt; G(y)-&gt;g(y) .

Surely Var(aX+b) = a²(Var(X))...always?! Ah never mind.

Ouch! How on earth are you taking S3 without having done C4 yet? I'm sure for S2-4 (and M2-4), that C1-C4 is a prerequisite.

I think that's chapter 1? I keep making stupid mistakes there.

Nope, if you have loads of observations, the errors tend to sort themselves out. As in, some will deviate to be higher than the mean, but some will deviate to be lower than the mean and the errors cancel. Whereas if you take one observation and multiply it, the error is amplified.

I did AS maths and further maths last year, with C1, C2, S1, FP1, M1, S2. A2 maths is C3, C4 and D1. A2 further maths is M2, D2 and FP2. I'm teaching myself S3, S4 and FP3 this year, possibly working through the M3&4 book after the June session's done. So yeah, I've had to look through bits of C3 and 4 early in order to do S2 and S3.

I'm going to ignore the middle paragraph there because I haven't revised S3 that much, but I'm sure there's something that looks wrong with what you said. I'll get back to you next week on that...

Oh I see...so you won't be taking C4 till June then? That's a shame. Eurgh I did M3 and M4 last June and got 50s and 60s in it - what a waste of time that was!

It's not really covered in that chapter, but I've had to use that before and it came out right.

Yeah, in May/June. Ouch, unlucky. What modules have you done then? That's pretty mechanics heavy.

Well I'm on a gap year now (or year 14 if you like ) but over the last 2 years I did C1-4, FP1-3, M1-4, S1-4. I ended up being too rusty on all the modules (clearly I did too many...) and got a B in FM (7 UMS off an A )- actually costing me my university place .

Ooh, a gap yah. TAKE ALL THE MODULES!

...which is exactly what I'm trying to do. Also annoying is that OCR don't do additional further maths, because we'd get an extra AS from that. Unlucky - are you re-applying this year?

Yeah haha, I was considering doing AFM with Edexcel in June - but cba to learn D1 and D2 (along with M3,4,5 again...). I think I'll just prepare for STEP (I need it for my offer anyway) to keep my maths 'strong'.

Yeah, I've reapplied this year. Which unis have you applied to btw?

Time to start properly revising S3...

How did you find that? This sounds really weird, but do you remember what you got for the first part of the last question? (I think it was 7 marks).

I messed up my test statistic and got a ridiculously large value of around 17 and rejected the null hypthesis...

And I was a bit stumped by E(|X|)...

No idea, I fell asleep once I finished. I was in a room with 2 others who also had clashes, and didn't get much sleep last night. What was the question on?

I just did E(X) but then put in 2 instead of -2 for the first integral.

What's interquartile range again? Q1-Q3, right?

Oh man it's bugging me so much because I lost around 5 marks on that. I was really relying on 90 UMS+ on this - but grade boundaries are always ridiculous for S3.

High or low? I'm hoping low

As soon as I saw that CRV question, I was annoyed. No CDF/PDF/related variables question - I like those.