Edexcel S2 Exam Paper January 2011 14/01/11

Been doing a few past papers and there seems to be a lot of questions on chapter 7 (hypothesis testing) :frown:

which can be a little confusing.
Does anyone have past papers from 2010? :smile:

Reply 2

Original post by cpdavis

Discuss all your enquiries and queries leading up to the exam :biggrin:

How are people preparing? Good luck :biggrin:

Subscribed :biggrin:

(I was expecting this from you when I saw C3...but I thought there was already one)

Reply 3

jit987

13

Original post by atofu

Been doing a few past papers and there seems to be a lot of questions on chapter 7 (hypothesis testing) :frown:

which can be a little confusing.
Does anyone have past papers from 2010? :smile:

Not started yet, but will start papers soon..

(edited 13 years ago)

Reply 4

jasbirsingh

11

Original post by cpdavis

Discuss all your enquiries and queries leading up to the exam :biggrin:

How are people preparing? Good luck :biggrin:

By doing past papers :s-smilie:

Reply 5

I have little problem in this question 3.
I have got part a-c correct but don't understand the answer to part d which edexcel provided on markscheme.
In part d, they specified that the robot break down twice but in part b the robot break down at least once(it can be more than twice), so why the answer to part d is equal to part b???

Thankss

Reply 6

Original post by jit987

Not started yet, but will start papers soon..

thanks for the papers :biggrin:

Reply 7

Original post by cazzy-joe

I have little problem in this question 3.
I have got part a-c correct but don't understand the answer to part d which edexcel provided on markscheme.
In part d, they specified that the robot break down twice but in part b the robot break down at least once(it can be more than twice), so why the answer to part d is equal to part b???

Thankss

Part D is asking for the probability of the robot breaking down in the next 8 hours (you ignore the bit where it says it broke down twice in the last 8 hours as it's not asking about that in the probability - poisson events are independent)
And in part B i , breaking down atleast once = breaking down so the answer is just the same.

I have a question, I don't understand the last part of this question in the june 2008 paper. It says find the probability of incorrectly rejecting the Ho, but in the answer they just worked out the probability of rejecting the Ho?
I don't see how they would be rejecting it incorrectly then. What i thought was working out the actual significance and do 5% - that to find the probability of it being rejected, if 5% was the one they used instead of the actual significance.. if that makes sense :confused:

(edited 13 years ago)

Reply 8

jit987

13

Original post by atofu

I have a question, I don't understand the last part of this question in the june 2008 paper. It says find the probability of incorrectly rejecting the Ho, but in the answer they just worked out the probability of rejecting the Ho?
I don't see how they would be rejecting it incorrectly then. What i thought was working out the actual significance and do 5% - that to find the probability of it being rejected, if 5% was the one they used instead of the actual significance.. if that makes sense :confused:

Yeh, that is weird. The mark scheme would be right if they question said 'Probability of rejecting Ho'.

Can anyone explain why the MS for Jan 2007 Question 3b) says is P(W>or equal 7). Where and how do I get that?
Thanks.

Reply 9

Original post by jit987

Yeh, that is weird. The mark scheme would be right if they question said 'Probability of rejecting Ho'.

Can anyone explain why the MS for Jan 2007 Question 3b) says is P(W>or equal 7). Where and how do I get that?
Thanks.

Each box has 12 flowers, to get more white flowers you would need atleast 7 of the flowers to be white which is p(w> or equal to 7)

Reply 10

Original post by atofu

Part D is asking for the probability of the robot breaking down in the next 8 hours (you ignore the bit where it says it broke down twice in the last 8 hours as it's not asking about that in the probability - poisson events are independent)
And in part B i , breaking down atleast once = breaking down so the answer is just the same.

But then even part c is also breaking down (two times) then why cant answer d be that??

I have a question, I don't understand the last part of this question in the june 2008 paper. It says find the probability of incorrectly rejecting the Ho, but in the answer they just worked out the probability of rejecting the Ho?
I don't see how they would be rejecting it incorrectly then. What i thought was working out the actual significance and do 5% - that to find the probability of it being rejected, if 5% was the one they used instead of the actual significance.. if that makes sense :confused:

Yeahh I think they found out probability for REJECTING Ho.
So then probability of INCORRECTLY REJECTING would be 1-0.0433=0.9567???

Reply 11

jit987

13

Original post by atofu

Each box has 12 flowers, to get more white flowers you would need atleast 7 of the flowers to be white which is p(w> or equal to 7)

Alright

Reply 12

Original post by cazzy-joe

But then even part c is also breaking down (two times) then why cant answer d be that??

For part D they are asking the prob. that the robot will break down at all, so that could mean breaking down once, twice, 3 times etc. etc.
which is the same as the probability of breaking down atleast once (part b)
Part c is just specific to the robot breaking down twice, but if it did break down at all, it could be more or less than breaking down 2 times.. if you get what i mean xD

Reply 13