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probability question
Posted: Fri Mar 06, 2015 5:54 am
by entropi
If you choose an answer to this question at random, what is the chance you will be correct?
(A) 25% (B) 50% (C) 60% (D) 25%
Re: probability question
Posted: Fri Mar 06, 2015 5:59 am
by Amelia
It depends.
Re: probability question
Posted: Fri Mar 06, 2015 6:01 am
by Bill Spight
Posted: Fri Mar 06, 2015 6:07 am
by EdLee
Question X:
If you choose an answer to Question X at random, what is the chance you will be correct?
Please first define Question X.
Re: probability question
Posted: Fri Mar 06, 2015 6:10 am
by schawipp
To make things more desperate you should extend this to ...
If you choose an answer to this question at random, what is the chance you will be correct?
(A) 20% (B) 50% (C) 60% (D) 20% (E) 0%
Re:
Posted: Fri Mar 06, 2015 6:52 am
by entropi
EdLee wrote:Question X:
If you choose an answer to Question X at random, what is the chance you will be correct?
Please first define Question X.
EdLee, the question refers to itself. So, "this question" is the question you read.
Re: probability question
Posted: Fri Mar 06, 2015 7:09 am
by DrStraw
entropi wrote:If you choose an answer to this question at random, what is the chance you will be correct?
(A) 25% (B) 50% (C) 60% (D) 25%
Zero. Without further information we can only assume that all answers are possible. Therefore the choices form a finite subset of an infinite number of possible answers. The density is zero.
If, on the other hand, all possible correct answers are listed and each is considered equally likely then the probability is one third.
Re: probability question
Posted: Fri Mar 06, 2015 7:13 am
by RBerenguel
DrStraw wrote:entropi wrote:If you choose an answer to this question at random, what is the chance you will be correct?
(A) 25% (B) 50% (C) 60% (D) 25%
Zero. Without further information we can only assume that all answers are possible. Therefore the choices form a finite subset of an infinite number of possible answers. The density is zero.
If, on the other hand, all possible correct answers are listed and each is considered equally likely then the probability is one third.
Measure or (in some cases, depending on the use)
capacity is zero. A set does not
have density, but is either dense or not (depending on a metric.)
Re: probability question
Posted: Fri Mar 06, 2015 7:16 am
by DrStraw
RBerenguel wrote:DrStraw wrote:entropi wrote:If you choose an answer to this question at random, what is the chance you will be correct?
(A) 25% (B) 50% (C) 60% (D) 25%
Zero. Without further information we can only assume that all answers are possible. Therefore the choices form a finite subset of an infinite number of possible answers. The density is zero.
If, on the other hand, all possible correct answers are listed and each is considered equally likely then the probability is one third.
Measure or (in some cases, depending on the use)
capacity is zero. A set does not
have density, but is either dense or not (depending on a metric.)
Agreed. But most people here are not mathematicians. As I was writing in English I used a term which I would expect to be clearer to everyone.
Re: probability question
Posted: Fri Mar 06, 2015 7:28 am
by RBerenguel
Got it, I just read it in mathematician eyes but now I think of it I can't find a clearer English word aside from density. Weird, I bet there should be one...
Re: probability question
Posted: Fri Mar 06, 2015 7:50 am
by RobertJasiek
Since it may be any random distribution with any probability, there are an infinite number of such probabilities but only a finite number of available answer probabilities. Hence the answer is: "almost 0". With a model of an increasing number of distributions and finally infinitely many, the answer is: "converges to 0 from its positive side".
Re: probability question
Posted: Fri Mar 06, 2015 7:59 am
by Fedya
I'm reminded of the mathematician joke that ends with the punchline, "The mathematician picks up the flamethrower and sets the house on fire, thereby reducing the problem to a case previously solved."
Re: probability question
Posted: Fri Mar 06, 2015 9:10 am
by Bill Spight
RobertJasiek wrote:Since it may be any random distribution with any probability, there are an infinite number of such probabilities but only a finite number of available answer probabilities. Hence the answer is: "almost 0". With a model of an increasing number of distributions and finally infinitely many, the answer is: "converges to 0 from its positive side".
In English "to choose at random" means to choose so that each option has the same probability of being chosen.
Re: probability question
Posted: Fri Mar 06, 2015 9:23 am
by Joelnelsonb
%0.0 Chance given that the correct answer is not actually listed.
Re: probability question
Posted: Fri Mar 06, 2015 10:46 am
by RobertJasiek
Bill Spight wrote:In English "to choose at random" means to choose so that each option has the same probability of being chosen.
I'd say that "to choose at random uniformly / with a uniform distribution" would mean this. At least in (precise) German, one needs to say "gleichverteilt zufällig wählen".