Edexcel S3 - How was it?

hmjessop

13

I thought it was a standard paper, very similar to past papers. I hated the 10 mark :eek:

question about sampling though!

What did everyone else think?

Reply 1

mrhenryh

I forgot how to calculate variance on the first question. Other than that, and the written Qs, may have got the rest right. Then again, always easy to make little mistakes here and there. I think it was slightly more difficult than previous papers

Reply 2

hmjessop

OP

13

Yeah, in stats, even if you can do all the questions, you always make a calculation error somewhere along the way that messes up the whole question. Usually with variance for me :biggrin:

Reply 3

mikeleeds

Ye pretty standard. Theyre always the same.
S4 tomorow!!

I got the mean wrong on the first question though haha took me 2 checks through to notice!

Reply 4

Berto90

11

Anyone remeber which hypotheses they accepted/rejected?

Reply 5

gold_dust

how did everyone draw those scatter graphs?! The first one was okay but the second part was slightly odd..

Reply 6

Berto90

11

gold_dust

how did everyone draw those scatter graphs?! The first one was okay but the second part was slightly odd..

The second part was r(s) = -1 but r > -1 wasn't it?

Which basically meant that if you ranked them in order all five points decreased on the y axis with every step up on the x axis, but r > -1 meant it wasn't a straight line relationship. I kinda drew a curve downwards, a bit like an e^-x graph.

Reply 7

mrhenryh

Ha yeah forgot about them. Didn't have a clue for the second, I just drew a roughly negative correlation, as it stated negative but greater than -1.

For hypotheses..

judges agreed
girls and boys had a difference in expenditure
binomial was fine (might have forgotten what i put there) for the plants
girls and boys had correlation with subject choice
low chance of men weighing more than 1.5women (about 0.29), high chanace of 4 mean weighing less than 350 (about 0.8)

Reply 8

Berto90

11

mrhenryh

Ha yeah forgot about them. Didn't have a clue for the second, I just drew a roughly negative correlation, as it stated negative but greater than -1.

For hypotheses..

judges agreed
girls and boys had a difference in expenditure
binomial was fine (might have forgotten what i put there) for the plants
girls and boys had correlation with subject choice
low chance of men weighing more than 1.5women (about 0.29), high chanace of 4 mean weighing less than 350 (about 0.8)

Yeah all in agreement with that, except "low chance of men weighing more than 1.5women (about 0.29)" which i do agree with, but I think the question was worded 'What is the probability one man will weigh LESS than 1.5 times that of a woman', so the actual probability in the answer was around 0.7....
I'm not too sure though, I really can't remember the question too well.

Reply 9

RJA

2

It was P(M<1.5W) = P(M-1.5W<0)
Work out the distribution of (M-1.5W) and find the phi value.

I thought the paper was alot easier than I expected :smile:

Reply 10

mrhenryh

Ah sugar. Oh well, probably only one mark dropped on that one. Annoying as I finished with loads of time to spare but that was the only one I didn't check through..

Reply 11

BurningSnowman

1

Does variance 27.0 ring a bell (pun intended) with anyone? I managed to spend the last 2 minutes panicking because what should have been a slightly rounded calculation check to ensure I was in the right ballpark came to something totally different, more than once.

I think my resulting CI was (165.8, 170.1). Anyone remember if they got this?