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4 Jun 2003, 12:44
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#1
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Checkout Boy
Join Date: Jun 2002
Posts: 622
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maths help
ta
Anne plays a game, 6 sided fair die if she rolls
1,2,3 she loses £10
4,5 she wins £x
6 she wins £2x
show that the e(X) of annes profit is £(2/3x-5) in a single game
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Last edited by Tobe; 4 Jun 2003 at 13:03.
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4 Jun 2003, 12:46
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#2
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Banned
Join Date: Jan 2003
Posts: 554
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I can't believe I've failed so much in maths.
I haven't got a clue what the answer is, but I know this is pish easy.
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4 Jun 2003, 12:48
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#3
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Checkout Boy
Join Date: Jun 2002
Posts: 622
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i know but the p(b|a) ones always confuse me
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David Dickinson says:
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4 Jun 2003, 12:54
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#4
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Lord Denning
Join Date: Feb 2003
Location: City of London
Posts: 2,548
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Well there are 10 with nuts, of which 6 have hard centres, so I'd guess the probability is 3/5.
And I'd guess e(x) is 7.5, although the question doesn't appear to make sense, as x could be anything...
By the way, Statistics is evil.
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Quote:
Originally Posted by Marilyn Manson
He was crowned in York Cathedral as 'Expert in the West' by Pope Urban III in 1186.
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4 Jun 2003, 12:55
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#5
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dim like a fox
Join Date: Apr 2000
Location: Finland ffs
Posts: 866
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Re: maths help
Quote:
Originally posted by Tobe
13 hard centre, of these 13, 6 contain nuts
7 soft centre, of these 7, 4 contain nuts
find p of it having a hard centre given it contains a nut
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isn't this the same as "contains a nut AND has a hard center" ?
In which case it would be 10/20 * 6/10
where 10/20 is the chance of finding a nut and 6/10 is the chance of finding a hard center.
Or if you already HAVE the information that it does indeed contain a nut then it would just be 6/10.
i might be very wrong though.
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4 Jun 2003, 12:55
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#6
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Next goal wins!
Join Date: Sep 2000
Location: London
Posts: 5,406
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Re: maths help
Quote:
Originally posted by Tobe
20 chocolates
13 hard centre, of these 13, 6 contain nuts
7 soft centre, of these 7, 4 contain nuts
find p of it having a hard centre given it contains a nut
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it contains a nut... so that means it can only be one of 10... um... the way im thinking it should just be 60% or whatever. but thats far too easy...
poo
but i dont see why the ones that dont have nuts in should be counted at all... as you have already taken one that contains a nut, unless i misunderstand you.
cant you just ignore the 3 nutless soft and 7 nutless hards completely? leaving you with 6 nutted hard and 4 nutted soft? IT ALREADY SAID IT CONTAINED A NUT...
oh bah
im sure im wrong, because like i said its far too easy. but 60% heh.
(P.S i got an E in a level maths... so there are some more points stacked against me)
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bastard bastard bastard bastard
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4 Jun 2003, 12:55
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#7
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dim like a fox
Join Date: Apr 2000
Location: Finland ffs
Posts: 866
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Quote:
Originally posted by Proteus
Well there are 10 with nuts, of which 6 have hard centres, so I'd guess the probability is 3/5.
And I'd guess e(x) is 7.5, although the question doesn't appear to make sense, as x could be anything...
By the way, Statistics is evil.
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Luckily this isn't statistics.
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4 Jun 2003, 12:57
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#8
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Lord Denning
Join Date: Feb 2003
Location: City of London
Posts: 2,548
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Quote:
Originally posted by menth0l
Luckily this isn't statistics.
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It's probability, so of course it's statistics.
__________________
Please bear in mind when reading the above post that I am always right.
Quote:
Originally Posted by Marilyn Manson
He was crowned in York Cathedral as 'Expert in the West' by Pope Urban III in 1186.
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4 Jun 2003, 12:58
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#9
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Checkout Boy
Join Date: Jun 2002
Posts: 622
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i hate given that questions although i see its 3/5 for q 2
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David Dickinson says:
you're desperate in virtually every aspect of your life
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4 Jun 2003, 12:59
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#10
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dim like a fox
Join Date: Apr 2000
Location: Finland ffs
Posts: 866
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Quote:
Originally posted by Proteus
It's probability, so of course it's statistics.
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probability is an area of mathematics.
so is statistics.
this is probability.
this is not statistics.
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4 Jun 2003, 13:03
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#11
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Lord Denning
Join Date: Feb 2003
Location: City of London
Posts: 2,548
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Quote:
Originally posted by menth0l
probability is an area of mathematics.
so is statistics.
this is probability.
this is not statistics.
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The exam boards would disagree with you.
__________________
Please bear in mind when reading the above post that I am always right.
Quote:
Originally Posted by Marilyn Manson
He was crowned in York Cathedral as 'Expert in the West' by Pope Urban III in 1186.
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4 Jun 2003, 13:06
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#12
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Checkout Boy
Join Date: Jun 2002
Posts: 622
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Quote:
Originally posted by Proteus
The exam boards would disagree with you.
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the exam board calls the paper probability and statistics 1
__________________
David Dickinson says:
you're desperate in virtually every aspect of your life
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4 Jun 2003, 13:08
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#13
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dim like a fox
Join Date: Apr 2000
Location: Finland ffs
Posts: 866
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Quote:
Originally posted by Proteus
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Statistics applies some bits of probability. Does not mean that all probability is automatically statistics.
Screw the exam boards, i work with statistics for a living
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Nobody's perfect.
I'm perfect.
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ph33r TPE plz. thxbye.
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4 Jun 2003, 13:09
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#14
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Lord Denning
Join Date: Feb 2003
Location: City of London
Posts: 2,548
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Quote:
Originally posted by menth0l
Statistics applies some bits of probability. Does not mean that all probability is automatically statistics.
Screw the exam boards, i work with statistics for a living
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I did this kind of probability in a statistics exam.
__________________
Please bear in mind when reading the above post that I am always right.
Quote:
Originally Posted by Marilyn Manson
He was crowned in York Cathedral as 'Expert in the West' by Pope Urban III in 1186.
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4 Jun 2003, 13:13
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#15
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dim like a fox
Join Date: Apr 2000
Location: Finland ffs
Posts: 866
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Quote:
Originally posted by Proteus
I did this kind of probability in a statistics exam.
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Yes, because obviously basic probability is something you need to know to be able to do statistics.
Jesus ****ing christ.
I'm through arguing about this.
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ph33r TPE plz. thxbye.
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4 Jun 2003, 13:16
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#16
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Registered User
Join Date: Oct 2001
Posts: 940
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Re: maths help
Quote:
Originally posted by Tobe
ta
Anne plays a game, 6 sided fair die if she rolls
1,2,3 she loses £10
4,5 she wins £x
6 she wins £2x
show that the e(X) of annes profit is £(2/3x-5) in a single game
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(-10 * (1/2)) + (x * (1/3)) + (2x * (1/6)) =e(x)
= -5 + (x/3) + (x/3)
= (2x/3) - 5
If you are going to use brackets at least use them correctly Tobe as the answer you ask for is wrong
Last edited by MrPeach; 4 Jun 2003 at 13:22.
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4 Jun 2003, 13:17
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#17
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Lord Denning
Join Date: Feb 2003
Location: City of London
Posts: 2,548
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Quote:
Originally posted by Tobe
the exam board calls the paper probability and statistics 1
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Not my exam board.
__________________
Please bear in mind when reading the above post that I am always right.
Quote:
Originally Posted by Marilyn Manson
He was crowned in York Cathedral as 'Expert in the West' by Pope Urban III in 1186.
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