Edexcel S3 - Wednesday 25th May AM 2016

Better image.



Posted from TSR Mobile

$P(X \leq -0.1) \neq 1 - P(X \leq 0.1)$

The distribution of X is not centered around 0, it's centered around 0.1

You want:
$P(X \leq -0.1) = 1 - P(X \leq 0.2)$

$P(Z \leq -0.1) = 1 - P(Z \leq 0.1)$

I just realised you use mobile. I hope you can visualise LaTeX

I guessed that was the problem but just wanted to make sure. but then my brain said "mate tis still a bell shape". im happy i got 3 questions in a row correct been a good night lol.

Meh I've probably done less than that

Still don't get what I'm supposed to be doing in some of these Ch1 questions from madas booklet

Does anyone know if we need to know about lottery sampling?

I think so since it is in the book.


Posted from TSR Mobile

True, just found it strange that there were no exercise questions about it and that it didn't appear in the end of chapter summary.

Any good notes for S3 sampling about?

Any good notes for S3 sampling about?

The book is simple tbh for this.

Learn adv/dis etc.

A onne marker they could ask is which sampling method is non-random which is quota sampling.

The book is most likely all you need, and looking at past paper questions. It's just slightly confusing wrt quota sampling vs stratified sampling but

This might be worth looking at if you are stuck.

Alright, thanks to both of you.

Can't remember much of the methods at the moment that's all

I have almost completed my online notes on sampling. On quota atm. Systematic and random are the most obvious I feel, but brush up on quota and stratified as they haven't been asked for a while I think.

I haven't touched the recent papers yet, still doing the Solomon. Sampling is slowly coming to me the more I get them wrong and review the mark schemes thankfully

The boundaries in S3 are pretty tough though I think, I'm fairly sure bar last year it's nearly always 75 for 100 UMS

Anyone got any good notes covering all memory needed for the sampling chapter 2 stuff?

Chapter 1 I think is key. You need to know when to square the variance and when not too. This is the difference between gettin 0 or 12 / 12 on the ND question.

Chapter 5 is really easy, they ask the same **** every year, once you have done enough practice the questions never change. Chapters 3 and 4 are the ones I will focus on now. Done my recapping of the S1 percentage points, will hopefully be finished by end of sunday/monday and do all the papers. I have pretty much targetted chapter 5 and 1 questions from past papers.

Yes true, not much can be done about that tbh!

I agree, just gotta work on my Chapter 5. I was caught out by a question in a solomon paper, basically they gave a table but they wanted you to modify the table and then calculate the coefficient. Quite clever question actually

Could you post a link and q number please?