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Edexcel S2 - 27th June 2016 AM

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Original post by iMacJack
Got the same as you for everything apart from the n=225 which I messed up on, well done they're all correct (from memory)


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Ye for that question some people put in 0.2n and 0.16n straight into normal parameters you could have just put mue and standard devation squared and then at the end find n.
i think i might have lost 1 mark for 41.875 should have rounded t to 41.88 since its money
What would 53 marks be in UMS wise?


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Original post by imran_
What would 53 marks be in UMS wise?


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proabably a mid/high C so anywhere between 64-69
guys, for qs 3, Area = pie R², so E(A) = E(pie R²) : pie x E(R²). you then workt out E(R²) = Var(R) + ( E(R) ) ². the values were 5 and 9, do the math, the answer is 151/3 pie
does anyone know how many marks each question was
Eyyy that was an easy paper. Didnt expect that
Original post by asacred
guys, for qs 3, Area = pie R², so E(A) = E(pie R²) : pie x E(R²). you then workt out E(R²) = Var(R) + ( E(R) ) ². the values were 5 and 9, do the math, the answer is 151/3 pie


It was 49pi
Original post by ISAAQAHELP
Ye for that question some people put in 0.2n and 0.16n straight into normal parameters you could have just put mue and standard devation squared and then at the end find n.
i think i might have lost 1 mark for 41.875 should have rounded t to 41.88 since its money


I got 200 something ffor the n but Im sure it wasnt 225
Original post by fpmaniac
It was 49pi


can you please explain how did you get that ? instead of just saying "ur wrong "
Original post by ISAAQAHELP
Q1-
1.41=1.4419 so mean=varaiance so use poisson
0.2510
0.7769
0.1378
0.1516

Q2-
n=60
0.0133
0.0159
not sure about this one someone please reply to this one: 23.69%>1% accept H0.

Q3-
1/2
151PI/3 REPLY TO THIS as well PLZ

Q4-
B=8
A=-12
K=1/9

Q5-
N=225

Q6-
57


Q7-
1.2
0.24
41.875 AND 40 REPLY TO THIS ONE IT IS ABOUT THE MONEY LAST ONE.


Pretty sure it was 49pi and i got other answer for n=225, I got n=200 something
Original post by asacred
can you please explain how did you get that ? instead of just saying "ur wrong "


I found what E(R) was (a+b/2) then A=piR2 So you had to square E(R) to get (E(R))2 and times by pi which will give you E(A)
Original post by fpmaniac
I found what E(R) was (a+b/2) then A=piR2 So you had to square E(R) to get (E(R))2 and times by pi which will give you E(A)


squarring e(R) does not equal E(R²)....
Original post by asacred
can you please explain how did you get that ? instead of just saying "ur wrong "


You had to work out E(A)=E(piR^2)=piE(R^2) the reason you got 49pi is because you thought that E(R^2)= (E(R))^2 which it doesnt it is (E(R))^2+var(R) or just integrate it funny because this question is in the s2 book as an example but with different numbers obviously.
Original post by igotohaggerston
You had to work out E(A)=E(piR^2)=piE(R^2) the reason you got 49pi is because you thought that E(R^2)= (E(R))^2 which it doesnt it is (E(R))^2+var(R) or just integrate it funny because this question is in the s2 book as an example but with different numbers obviously.


ikr, i got it right, you quoted the wrong person x)
For all of those still debating wherever the answer is 151/3 pi or 49 pi,

Here I've attached a similar past paper question and the mark scheme as the question we've done today.

I only done this yesterday so it prepared me very well for today :P.
Question.pdf10.9KB
Mark Scheme.pdf108.7KB
Original post by asacred
squarring e(R) does not equal E(R²)....


Honestly I dont remember what I did but I might havae got it wrong looking back on it and you might be right. I was going to do it the other way (VAR) way but I didnt have enough time so I had to choose between the one way :P
Original post by igotohaggerston
You had to work out E(A)=E(piR^2)=piE(R^2) the reason you got 49pi is because you thought that E(R^2)= (E(R))^2 which it doesnt it is (E(R))^2+var(R) or just integrate it funny because this question is in the s2 book as an example but with different numbers obviously.


Lol yeah! I even looked at it in the morning such a shame still got it wrong. What marks do you think I would get for that Question
Original post by fpmaniac
Pretty sure it was 49pi and i got other answer for n=225, I got n=200 something


R-U[5,9]

A=piR"

E(A)=pi*E(R")

E(R)=(5+9)/2=14/2=7

VAR(R)=(9-5)"/12=16/12=4/3

VAR(R)=E(R")-[E(R)]"
E(R")=VAR(R)+[E(R)]"

E(R")=(4/3)+(7)"
E(R")=(4/3)+49

E(R")=151/3

E(A)=151pi/3
" means squared.
Original post by ISAAQAHELP
R-U[5,9]

A=piR"

E(A)=pi*E(R":wink:

E(R)=(5+9)/2=14/2=7

VAR(R)=(9-5)"/12=16/12=4/3

VAR(R)=E(R":wink:-[E(R)]"
E(R":wink:=VAR(R)+[E(R)]"

E(R":wink:=(4/3)+(7)"
E(R":wink:=(4/3)+49

E(R":wink:=151/3

E(A)=151pi/3
" means squared.


Yeah I realised where I went wrong. Oh well
Original post by ISAAQAHELP
R-U[5,9]

A=piR"

E(A)=pi*E(R":wink:

E(R)=(5+9)/2=14/2=7

VAR(R)=(9-5)"/12=16/12=4/3

VAR(R)=E(R":wink:-[E(R)]"
E(R":wink:=VAR(R)+[E(R)]"

E(R":wink:=(4/3)+(7)"
E(R":wink:=(4/3)+49

E(R":wink:=151/3

E(A)=151pi/3
" means squared.


Yup. Perfect.

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