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S1 Jan 2012 Edexcel Post Exam Discussion Thread - Solutions in the first post

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Reply 20
Avatar for battsa
battsa
Whether the correlation was negative or positive, the PMCC would still increase.
Reply 21
Avatar for POWW!
POWW!
12
Ok your predicted grade boundaries have to be wrong or I'm gonna cry come march
Reply 22
Avatar for vishalb
vishalb
Original post by Musical-Ocean
Increases in the sense that the correlation increases, but decreases in the numerical sense.
I answered the Q just like arsey did, better get the marks !!!


But that means that the question wasn't phrased very well :frown:
It could've been interpreted in 2 different ways?
arsey dont u think 70 marks for 90 ums is so high

Seroiselly :/
Reply 24
Avatar for Fardip
Fardip
Original post by IAmTheChosenOne
:p: I'm getting confused now.. So decrease -> stronger correlation, right?


Read the question properly,... It asks what'd happen to the VALUE of the pmcc.. You're right by saying the correlation will decrease.. But the value of the correlation will increase.. Get it now? :smile: x
(edited 12 years ago)
Reply 25
Avatar for Fardip
Fardip
Original post by vishalb
But that means that the question wasn't phrased very well :frown:
It could've been interpreted in 2 different ways?


lol It literally asks what'd happen to the VALUE of the pmcc, not the pmcc itself.. :/
Reply 26
Avatar for Fardip
Fardip
Original post by Qaisar Khan
arsey dont u think 70 marks for 90 ums is so high

Seroiselly :/


LOOL Qaisar is here as well!! LOL bro, that paper was a good paper... I think he's right with the grade boundaries.. :/
Reply 27
Avatar for vishalb
vishalb
Original post by Fardip
lol It literally asks what'd happen to the VALUE of the pmcc, not the pmcc itself.. :/


lol yeah so the VALUE would decrease? A negative number would decrease to get closer to -1?
Original post by POWW!
This has been harder for me then the other papers. :l Counted 65 :l


Some candidates are entered in the Winter, and most often do it in the Summer when better prepared etc. It was a good paper if you had prepared well, although alot of others I spoke to said it was extremely tricky in parts. Boundaries most definately higher than June11. The June12 paper is set to be a challenging one no doubt.
I wouldve lost about 3 marks from the whole paper if it wasnt for that freakin' question 2 .. 8 MARKS LOST ON ONE QUESTION :angry:
And i still dont get it even by looking at the answer :s-smilie:
Can someone explain it to me ...
Original post by Fardip

Original post by Fardip
LOOL Qaisar is here as well!! LOL bro, that paper was a good paper... I think he's right with the grade boundaries.. :/


yh i knw but thts berrrs thts like 93%
Original post by Fardip
lol It literally asks what'd happen to the VALUE of the pmcc, not the pmcc itself.. :/



Original post by vishalb
lol yeah so the VALUE would decrease? A negative number would decrease to get closer to -1?



VALUE should decrease, shouldn't it? :holmes:
Reply 32
Avatar for Sheevang
Sheevang
2
Original post by vishalb
for the pmcc increasing/decreasing question - if as time goes by, weirght decreases shouldn't the outlier mean there is a decrease in the PMCC and a stronger negative correlation?


I totally agree with you and this is what I put!
Reply 33
Avatar for POWW!
POWW!
12
Original post by intellectual1
Some candidates are entered in the Winter, and most often do it in the Summer when better prepared etc. It was a good paper if you had prepared well, although alot of others I spoke to said it was extremely tricky in parts. Boundaries most definately higher than June11. The June12 paper is set to be a challenging one no doubt.

I was prepared, I was getting 100's on past papers...

Original post by shooby_doo
I wouldve lost about 3 marks from the whole paper if it wasnt for that freakin' question 2 .. 8 MARKS LOST ON ONE QUESTION :angry:
And i still dont get it even by looking at the answer :s-smilie:
Can someone explain it to me ...


It was independent so P(AnB)= P(A) x P(B)
you sub that in
Reply 34
Avatar for Fardip
Fardip
Original post by vishalb
lol yeah so the VALUE would decrease? A negative number would decrease to get closer to -1?


yeah that's right, the value should decrease.. I'm hoping Arsey made a mistake there too... :biggrin:
Reply 35
Avatar for battsa
battsa
I really liked question two, it was quite clever...just me? Okay. :P
Reply 36
Avatar for Legendary
Legendary
1
M2 all over again 72 for 90 ums. :s-smilie:
Reply 37
Avatar for sanjeevp
sanjeevp
Fardip I'm afraid you and Arsey are wrong, it specifically asks for the change in PMCC therefore an anomalous value of 20g which is above the calculated value in the part before shows that this value has increased the PMCC therefore taking this out of the data means that it will decrease getting closer to -1
May I say you just got lawyered :smile:
Original post by POWW!
I was prepared, I was getting 100's on past papers...



It was independent so P(AnB)= P(A) x P(B)
you sub that in


What i dont undestand is he wrote
P(AnB) = P(A) + P(B) - (PAuB)

Isnt it ... P(AuB) = P(A) + P(B) - P(AnB)

It sounds like i need to brush up on my probabilities ...



Edit: Oh feck their the same thing ... woopzy
(edited 12 years ago)
Original post by Fardip
yeah that's right, the value should decrease.. I'm hoping Arsey made a mistake there too... :biggrin:


The outlier goes against the negative correlation
Therefore it weakens the correlation so it will oppose it.
It will go further away from -1

And referring to the r value this means the product moment correlation coefficient will increase

The correlation decreases , but when referring to product moment correlation ... you would reffer to the r value ..


Edit: Nope i iz wrong again ... missed the part where it says "The exclusion of the coin"
AHH GOD DARN IT! :frown:
(edited 12 years ago)

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