S2 Edexcel Tuesday 17th January SOLUTIONS IN FIRST POST

I did some genius ****t :P

Like P(X>>1) >> 0.95

Then P(X=0) << 0.05

Then (0.85)^x <<0.05

Then got x as 19

Bang!

Full Marks :smile:

Afaik that's what you were supposed to do

Reply 381

Rahul.S

14

for 4d I got 18....:/

i did 1-(0.85)^n>0.95
used ln etc.
n<18.....
n=18

reason why I was thinking twice about 18 as it said minimum

the rest of the paper was fine....did anyone adopt another method for this question?

i will consider this a decent performance considering I was 5 mins late for my exam! :tongue:

and didnt get the time back...

Reply 382

Xplolode

2

it doesn't matter....it's just a symbol

i used x to equal the answer

Reply 383

ilovemath

2

for the prove k = ... who used the area of a trapezium?

Reply 384

Xplolode

2

Original post by sqwerty

Afaik that's what you were supposed to do

But I didn't use any official method with Normal Distribution/Binomial or anything...just did my own ****t :P

Reply 385

Xplolode

2

Original post by ilovemath

for the prove k = ... who used the area of a trapezium?

no-one.

Reply 386

sqwerty

1

Original post by Rahul.S

for 4d I got 18....:/

i did 1-(0.85)^n>0.95
used ln etc.
n<18.....
n=18

reason why I was thinking twice about 18 as it said minimum

the rest of the paper was fine....did anyone adopt another method for this question?

i will consider this a decent performance considering I was 5 mins late for my exam! :tongue:

and didnt get the time back...

I did it this way then checked using 0.85^n and realised it was 19. Weird how it worked out

Reply 387

ilovemath

2

Original post by Xplolode

no-one.

lol
its just as right though
coz I worked out the area on the right was 0.5
so area trap = 0.5
and it worked :smile:

Reply 388

sqwerty

1

Original post by Rahul.S

for 4d I got 18....:/

i did 1-(0.85)^n>0.95
used ln etc.
n<18.....
n=18

reason why I was thinking twice about 18 as it said minimum

the rest of the paper was fine....did anyone adopt another method for this question?

i will consider this a decent performance considering I was 5 mins late for my exam! :tongue:

and didnt get the time back...

Anyway your offer is AA, worry about the 1,1 more!

Reply 389

Rahul.S

14

Original post by sqwerty

I did it this way then checked using 0.85^n and realised it was 19. Weird how it worked out

umm mathematically 18 is correct :/

but yh w.e. it is....I'm getting around 73-75 :tongue:

Is it me or that the boundaries will be similar to jan 2011?

Reply 390

Wireo

That really didn't go very well for me. I completely failed on question 2. And the pdf question I don't think I got the cdf right, meaning I doubt the last 2 parts of it were right either.

And somehow I got 20 for 4)d. I must have made a stupid error...

Reply 391

Xplolode

2

I spent 20mins on that stupid k question....

Luckily I still had 15mins left at the end :P

I integrated x -> x^2 not x^2/2....so kept getting the wrong answer

Eventually i realised and after 4 pages of work...got the answer right :biggrin:

Needed to use plenty of supplementary sheets^

Reply 392

Mathssss

8

what was the answer on the P ( 0.5 < x < 1.5) on the CDF question?

Reply 393

Rahul.S

14

Original post by sqwerty

Anyway your offer is AA, worry about the 1,1 more!

looooooooooooooooool

I did step I 2000 question 14 yesterday...its on S2 :tongue:

wbu? where have you applied? :biggrin:

Reply 394

ilovemath

2

Original post by Xplolode

I spent 20mins on that stupid k question....

Luckily I still had 15mins left at the end :P

I integrated x -> x^2 not x^2/2....so kept getting the wrong answer

Eventually i realised and after 4 pages of work...got the answer right :biggrin:

Needed to use plenty of supplementary sheets^

I didn't realise it was a quadratic at first..so I did the trapzeium coz I thought that would fix it
..well i got the same answer
k(k-1) = 1 but then realised it was quadratic
:smile:

Reply 395

Wireo

Do you know if anyone intends to post full worked answers to this paper?

Reply 396

GriffoPolitics

Original post by Xplolode

I spent 20mins on that stupid k question....

Luckily I still had 15mins left at the end :P

I integrated x -> x^2 not x^2/2....so kept getting the wrong answer

Eventually i realised and after 4 pages of work...got the answer right :biggrin:

Needed to use plenty of supplementary sheets^