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Probability question....
Posted: Sun Jul 08, 2012 2:48 pm
by countrymum
Would really like to understand this one....
For which of these can you work out the probability exactly?
A) It will rain tomorrow when class B go on a school trip.
B) Mr. Wood will pass his driving test
C) Stuart will miss the 8.30 am bus to school
D) Emily will throw heads when she tosses a coin
E) Amy will come third in a swimming competition
?????
Re: Probability question....
Posted: Sun Jul 08, 2012 2:52 pm
by Guest55
D is the only one where the outcomes are equally likely.
Two outomes Head or tail - probability of a Head is 1/2.
Re: Probability question....
Posted: Sun Jul 08, 2012 2:56 pm
by countrymum
Guest55 wrote:D is the only one where the outcomes are equally likely.
Two outomes Head or tail - probability of a Head is 1/2.
Thanks Guest55
What about passing/failing driving test isn't that 1/2 ( pass or fail )
Is this a straight forward one, have really struggled on it....
Re: Probability question....
Posted: Sun Jul 08, 2012 3:07 pm
by Manana
countrymum wrote:
B) Mr. Wood will pass his driving test
D) Emily will throw heads when she tosses a coin
Both these are 50/50
Re: Probability question....
Posted: Sun Jul 08, 2012 3:17 pm
by hermanmunster
I think that for the probability to be calculated you have to know that each outcome is equally likely . heads or tails is equally likely but passing or failing a test may not be equally likely
Re: Probability question....
Posted: Sun Jul 08, 2012 3:18 pm
by Guest55
Passing and failing a driving test are not equally likely - I think it varies from test centre to test centre and a driver could be appalling.
Theoretical probability only applies where 'skill' is not part of the picture - spinning a coin, throwing a die, etc.
Playing football depends on the teams playing - the weather depends on the time of year and the country.
Re: Probability question....
Posted: Sun Jul 08, 2012 3:19 pm
by dottie1974
Manana wrote:countrymum wrote:
B) Mr. Wood will pass his driving test
D) Emily will throw heads when she tosses a coin
Both these are 50/50
I guess someone is only likely to take their driving test if they think the odds are they are likely to pass - a coin toss has no element of skill (in that practice can have any outcome on the result you are likely to get)
Re: Probability question....
Posted: Sun Jul 08, 2012 3:27 pm
by countrymum
Guest55 wrote:Passing and failing a driving test are not equally likely - I think it varies from test centre to test centre and a driver could be appalling.
Theoretical probability only applies where 'skill' is not part of the picture - spinning a coin, throwing a die, etc.
Playing football depends on the teams playing - the weather depends on the time of year and the country.
Thanks everyone and guest55, thanks so much for that. It has all clicked and I get it now! Kind of thinking out of the box and taking many outside influences into account ( like for eg the weatherman mayhave got it wrong or like you say he may a rubbish driver etc etc )
Yes the answer is indeed D! If I get stuck again can I come back
You are all masters of maths
Re: Probability question....
Posted: Sun Jul 08, 2012 3:49 pm
by Guest55
I should hope so as I spend my life teaching it!