How was Edexcel S2?

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clare_m

yeah i think a got a mean of something like that. remind me how u did ures as i'm not sure if it was right, i simply integrated f(x) times x , with the limits being the 2 and 1......:-S....which i thought seemed v. wrong!!

and with the median i made F(x) ( the bit that was between 2 and 1) equal 0.5

again seemed a bit wrong, but at the same time, sort of right...!!!

please settle my mind. it may be wrong, but i dont care!!

yea i integrated the first part as well i.e. x times 1/3 between 0 and 1
and also the stuff wot u sed as well, then got my final answer for the mean

Reply 21

clare_m

DaKe

yea i integrated the first part as well i.e. x times 1/3 between 0 and 1
and also the stuff wot u sed as well, then got my final answer for the mean

but thats wot i think i got wrong, as i didnt do anything with the 1/3 bit. i thought about it, but then couldnt work out what i would do with it to get the mean. so i JUST used the answer from the integration times x of the line below (between 1 and 2)

oh well, hopefully got some of the marks

Reply 22

RussianDude

here are some answers that i can remember

4)c)0.1216 d)0.0024 e)mean=2, variance=1.8
3) 0.5754

Reply 23

Proteus

RussianDude

here are some answers that i can remember

4)c)0.1216 d)0.0024 e)mean=2, variance=1.8
3) 0.5754

4c) - I got 0.122, so yep i agree
4d) - i got 0.0024, yep
4e) mean = 2, variance = 1.8 - yep
3) 0.0713. i'm not sure where your answer comes from, it was a hypothesis test so i wouldn't expect the result to be that far away from 0.05 . . .

-Proteus

Reply 24

clare_m

i dont have a paper, i really cant remember. is there anywhere online that quickly works out and publishes the answers to the papers - how much would i love a person who did that!! cos its so difficult to asses how many marks you could be allocated from a wrong answer...grrr

Reply 25

clare_m

i got 0.07 something, i remember that both of the hypothesis has u keeping the ho hypothesis, as the results werent significant.

Reply 26

DaKe

Proteus

Yea i got that 2, 0.0713 but i rejected H0!!!! why? i dunno anotha stupid mistake.

Reply 27

2Pacalypse

I put minus 3 over 45 for the last cumulative thingy instead of plus 3 over 45 how many marks will i lose for this?
Both tests were not sig therefore keep H0

its 13/45 mate

2Pacalypse

I put minus 3 over 45 for the last cumulative thingy instead of plus 3 over 45 how many marks will i lose for this?
Both tests were not sig therefore keep H0

Yea u mite, because then ur F(x) doesn't add up to 1 like its supposed to.

yer ditto mike

oh crap...think i messed up the firt hypothesis testing and most of the last question. I'm thinkin the max i can get is 61...will that be enough for an A?

Reply 32

clare_m

yep....JUST!!

if u get everything else spot on, which includes getting the wordy questions correct- some of those examiners are a bit harsh!!

Reply 33

clare_m

i need an average of 83% out of S1, S2 AND P3 - as i got 79% for M1, 79% for P2 and 73% for P1....hopefully i should get nearer the 90's on the papers so i wud have a comfy margin - but u can never be too sure!!
it would b sooo annoying to be so close to and A but not quite, it would make me think, "why did i even f**king bother!!" as no-one will know you worked for an A. they'll just think ure an average B person...grrr

Reply 34

equili3rium

am i right that you keep H0 both both tests?

Reply 35

Neutrinohunter

kept H0 on both hypothesis tests.

yeah same here

For the continuous random variable I got F(x) equal to x/3 for the first block then (2/45)(x^4) + 13/45 for the second part. I got out a median of 1.48 and guessed the skew was -ve because mean < median.

same here

Thought it was a very nice paper tbh.

Bit disappointed that i got the mean as 1 and the continuity correction the rong way but i think it was a very nice paper.

The median question was a bit tricky tho, but everyone seems to have got 1.48

Reply 36

AngelofnoColour

I thought the paper was ok, but theres one question that really bugged me. Question 6, you had a mean 0.05, then for part a) I approximated it as normal. Then for parts b) and c) I did binomial, cos I didnt understnd how you do p(x = 2) for normal.
For d) I used normal.

Could someone tell me if I was right or wrong?

Reply 37

clare_m

indeed, you are correct

Reply 38

Leekey

That was either the easiest S2 paper I have ever sat or it was the hardest. I think I did everything correctly but I kept waiting for a difficult git of a question and it just didn't seem to happen (think I might have failed due to the fact that I found it too easy).... :confused: