[Gibbo81]

(Original post by exam2k10)
Gibbo, what would say 60/75 would equate to in terms of UMS? 75?

I reckon 63 for an A so somewhere between 75 and 80



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[Gibbo81]

(Original post by Manishex)
How about if you put down range?

Should be fine


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[exam2k10]

(Original post by Gibbo81)
I reckon 63 for an A so somewhere between 75 and 80



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Thanks. Do you know how harshly Edexcel mark?

For example, for question 8) I used a binomial distribution and did X~B(10,0.6) and then did 1-P(X<=1) and got 0.9939. How many marks will I lose?

[Gibbo81]

(Original post by exam2k10)
Thanks. Do you know how harshly Edexcel mark?

For example, for question 8) I used a binomial distribution and did X~B(10,0.6) and then did 1-P(X<=1) and got 0.9939. How many marks will I lose?

For which bit?

[exam2k10]

(Original post by Gibbo81)
For which bit?

Question 8a) part 2 Cos I reckon I will lose 1 since I got the 1st part right

[nicsxox]

On question 5b where you had to find E(X), i did that part wrong but on part c) where you to find the variance, i did all the methods right but just used the wrong value of E(x) would I get error carried forward marks? Or would i just lose the marks completely?

[andrewpeters]

Does anyone guess at whether 66/67 would be enough for 90 UMS?

[raheem94]

(Original post by Gibbo81)
...

I failed to understand the sampling distribution question, so i just found the sampling distribution for median rather than range.
How many marks will i lose?

In the last question, last part, i didn't got the right answer but i did the few initial steps correct, ie , is there a chance that i will get 1 mark for it?

So if i get 2 marks in the sampling distribution question and 1 in the last part of the last question, then i have lost around 6 marks .

According to you, what will 69/75 be in terms of UMS?

[nakz_]

(Original post by andrewpeters)
Does anyone guess at whether 66/67 would be enough for 90 UMS?

i dont think so, i think u'll need 69 for 90 UMS. reckon 66 is about 85 86

[jukebox123]

(Original post by Arsey)
Okay I will later


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hey arsey, have you created an M3 thread yet?

[FO12DY]

Question 6 - for the sampling distribution, was it necessary to draw the table out for probability of the ranges?

I wasn't really sure what to do (apparently we weren't taught it, but people always say that when they're pissed at a question - I've not paid attention in too many S2 lessons to know) but the first thing I did was to draw up a table of probability of x against x being ball numbered one or two (rather than against the range being zero or one). I then wrote out the possible combinations, as Arsey did, and calculated the probability of each.

But was the table showing probability of each range the actual question, so to speak, and what you needed as a final answer? Regardless, I should have got some for working, I'm just interested as to what the question really was.


Fecked up on question 8, too, lol - didn't take (n - 1) off of 50 for the last part. I knew it was wrong I was just running out of time and couldn't get my head around what I was doing in real terms, so I missed the 50. Ah well, I think it was closer to correct than I thought so hopefully there's some method there.

[Arsey]

(Original post by jukebox123)
hey arsey, have you created an M3 thread yet?

http://www.thestudentroom.co.uk/show...0#post37798440

[andrewpeters]

(Original post by Arsey)
http://www.thestudentroom.co.uk/show...0#post37798440

Hey Arsey, could you guess at this year's S2 grade boundaries please? Or just what 90/80/70 UMS would be?

[jukebox123]

(Original post by andrewpeters)
Hey Arsey, could you guess at this year's S2 grade boundaries please? Or just what 90/80/70 UMS would be?

90 ums- 70/75
80 ums- 66/75
70 ums- 60/75

[knowledgecorruptz]

(Original post by jukebox123)
90 ums- 70/75
80 ums- 66/75
70 ums- 60/75

!? Serious? Last year it was 67 for 90 UMS...that was a fairly easy paper, tbh, so I reckon this year's will be around there...if not lower...I think 70's a little too high, as quite a few people messed up the sampling distribution q and the last one...just my opinion, tho

[Injin]

How many marks would i gain from the sampling distribution question if i did it like this:

(1,1,1)
(1,1,2) ect all the possible samples and then correctly calculated all the probabilities.
For the table i put them as follows
x = (3 ones) (2 ones, 1 two) (2 twos, 1 one) (3 twos)

and then wrote down the corresponding probabilities


Thanks!

[Dae93]

(Original post by Injin)
How many marks would i gain from the sampling distribution question if i did it like this:

(1,1,1)
(1,1,2) ect all the possible samples and then correctly calculated all the probabilities.
For the table i put them as follows
x = (3 ones) (2 ones, 1 two) (2 twos, 1 one) (3 twos)

and then wrote down the corresponding probabilities


Thanks!

I did EXACTLY what you did. And it's bugging me so much. I'm going to be pessimistic and say 1, possibly two marks but I've heard a few people say 3. I wish Yey had put the work range in bold! Then maybe I wouldn't have overlooked it!

[Phenylethylamine_]

(Original post by Injin)
How many marks would i gain from the sampling distribution question if i did it like this:

(1,1,1)
(1,1,2) ect all the possible samples and then correctly calculated all the probabilities.
For the table i put them as follows
x = (3 ones) (2 ones, 1 two) (2 twos, 1 one) (3 twos)

and then wrote down the corresponding probabilities


Thanks!

Well, I did the same thing! I asked Gibbo (guy who posted the solutions) and he said 3, max 4. I've seen on a lot of mark schemes, they usually give 3 marks for combinations. So, I hope we at least get 3 marks!! Otherwise, it would be a disappointment because we know what to do just missed the word 'range' lol.

[r.shangle]

(Original post by amoo94)
a few people i know got n=38

You get 38 if you use a normal approximation. But 35 is the correct answer.

[Mathssss]

(Original post by Gibbo81)
?

gibbo are you doing s3 solutions?