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Offline sridhar

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statistics
« on: May 02, 2011, 07:52:04 pm »
Hi any body help with this probability quiz plz!

Paul plays 2 games. the probability he wins exactly one game is 0.3 and the probability he looses both games is 0.28.

what is the probability he wins both games?
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Offline Most UniQue™

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Re: statistics
« Reply #1 on: May 02, 2011, 07:59:29 pm »
I think its either 0.3x0.3=0.09 or 1-0.28=0.72
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Offline sridhar

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Re: statistics
« Reply #2 on: May 02, 2011, 08:03:23 pm »
Thanks, but I am not sure but how about drawing a tree diagram
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Offline NotAbod

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Re: statistics
« Reply #3 on: May 02, 2011, 08:17:35 pm »
2 things
1st-pro is right its 0.3x0.3
2nd- wrong section
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Offline Arthur Bon Zavi

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Re: statistics
« Reply #4 on: May 03, 2011, 10:13:36 am »
Is the answer (9/112) ?

By the way, moving this to AS/A2 section of math.
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Offline NotAbod

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Re: statistics
« Reply #5 on: May 03, 2011, 11:25:14 am »
Welcome back fidato :D
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Offline SkyPilotage

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Re: statistics
« Reply #6 on: May 03, 2011, 12:04:51 pm »
Hmm i think its 1-0.28-0.3!!= 0.42
Because if he doesnt win both games he can either lose both or win only one ....
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Offline NotAbod

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Re: statistics
« Reply #7 on: May 03, 2011, 12:27:19 pm »
he can:
win both
lose both
win first, lose second
lose first, win second
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Offline SkyPilotage

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Re: statistics
« Reply #8 on: May 03, 2011, 12:34:57 pm »
Quote from: AboD on May 03, 2011, 12:27:19 pm
he can:
win both
lose both
win first, lose second
lose first, win second
You are perfectly right, however the probability 0.3 is the probablity he wins EXACTLY one game and not the probablity to win any game.
Did you get what I mean?
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Offline NotAbod

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Re: statistics
« Reply #9 on: May 03, 2011, 12:36:19 pm »
true. winning one game can be found by:
[probability of losing x probability of winning] + [probability of winning x probability of losing]
he can win the second or first
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Offline SkyPilotage

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Re: statistics
« Reply #10 on: May 03, 2011, 12:39:35 pm »
Quote from: AboD on May 03, 2011, 12:36:19 pm
true. winning one game can be found by:
[probability of losing x probability of winning] + [probability of winning x probability of losing]
he can win the second or first
My point is the the question already gave you the probability of winning one game which includes both winning first or second...
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Offline NotAbod

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Re: statistics
« Reply #11 on: May 03, 2011, 12:44:26 pm »
yes let me explain and answer this.
wat r all the chances in this game?
1-win both
2-lose both
3-win first, lose second
4-lose first, win second
probability of winning exactly one is given: 0.3, this include chance 3 and 4
probability of losing both is given: 0.28
sum of probabilities always add up to 1
let probability of winning both = y
0.28 + 0.3 + y = 1
y = 1- (0.28 + 0.3)
y = 0.42
probability of winning both is 0.42
« Last Edit: May 03, 2011, 12:51:53 pm by AboD »
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Offline SkyPilotage

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Re: statistics
« Reply #12 on: May 03, 2011, 12:48:18 pm »
Quote from: AboD on May 03, 2011, 12:44:26 pm
yes let me explain and answer this.
wat r all the chances in this game?
1-win both
2-lose both
3-win first, lose second
4-lose first, win second
probability of winning at least one is given: 0.3, this include chance 3 and 4
probability of losing both is given: 0.28
sum of probabilities always add up to 1
let probability of winning both = y
0.28 + 0.3 + y = 1
y = 1- (0.28 + 0.3)
y = 0.42
probability of winning both is 0.42
Ahaha dude just scroll up and look at my answer and yours  ;) I got 0.42 and u got 0.09
P.S: 0.3 is the probability of winning EXACTLY ONE not atleast one...
 
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Offline NotAbod

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Re: statistics
« Reply #13 on: May 03, 2011, 12:51:31 pm »
i didnt read the question good, so i gave a rong answer
didnt notice that u answered lol
problem solved
Right exactly one not atleast one, will edit it
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Offline SkyPilotage

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Re: statistics
« Reply #14 on: May 03, 2011, 12:53:23 pm »
Quote from: AboD on May 03, 2011, 12:51:31 pm
i didnt read the question good, so i gave a rong answer
didnt notice that u answered lol
problem solved
Right exactly one not atleast one, will edit it
(sigh) Finally!!  ::)
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