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# The Official Edexcel S2 Jan 2010 Thread watch

1. hi,

for question 3a. was it (19/20)^5 ?

anyone got c4 tommorow?
2. yeah your 3a is correct
3. (Original post by kosy91)
thanks, but are you sure it's not x-po(0.25)

and 1-(x>0)

because they both give similar answers (difference of 0.005 i think)
4. (Original post by 02shahni)
thanks, but are you sure it's not x-po(0.25)

and 1-(x>0)

because they both give similar answers (difference of 0.005 i think)
yes, it is supposed to be poisson... i dont know if your method is right but you do get the right answer.

for sure, you will get the A1 mark. you will lose a mark for coverting into 0.25 and another for using x=0
5. got 96 ^-^ but it doesnt matter since you need C3 and C4 to get an A*
6. i got 92/100 which i was pleased with!
7. got 94. i know what i got wrong, there was a question where it tries to trick you by making a P(A|B) thing but i should have remembered that results are independent in a poisson.
8. If anyone has the official mark scheme for this paper, please upload it and I will rep you
9. (Original post by Plato123)
If anyone has the official mark scheme for this paper, please upload it and I will rep you
Enjoy!
Attached Images
10. 30b_S2_January_2010_mark_scheme.pdf (266.1 KB, 218 views)
11. i got 96...and i am disappointed with it!
12. Hi. Does anyone have this paper? Or is it somewhere on this forum?
Thanks!
13. (Original post by ViolinGirl)
Hi. Does anyone have this paper? Or is it somewhere on this forum?
Thanks!

good luck
14. (Original post by 02shahni)

good luck
I checked. But only found a very poor version of it, which will not allow me to do the questions.
15. (Original post by ViolinGirl)
I checked. But only found a very poor version of it, which will not allow me to do the questions.
yeh, i see what you mean. perhaps try asking at school? they'll have copies of it. it doesn't seem to have been uploaded on past papers sites yet for some reason.
16. S2 January 2010.
Attached Files
17. QP.doc (47.0 KB, 136 views)
18. MS.doc (263.5 KB, 107 views)
19. didnt really understand qu 7 at all :|
20. (Original post by Noble.)
S2 January 2010.
LOVE YOU! THANKS!
21. Can someone help me with Question 3 on the June 2005 paper:

A rod of length 2L was broken into 2 parts. The point at which the rod broke is equally likely to be anywhere along the rod. The length of the shorter piece of rod is represented by the random variable X.

(a) Write down the name of the probability density function of X, and specify it fully.

In the mark scheme it says Uniform Rectangular and I understood that.

But then why does it say

f(x) = { 1/L 0< X <= L
0 otherwise

Why are they saying 1/L? Where are they getting this from???
22. del

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