How to distinguish btw a Perms/Combs question and a Binomial Probability question? (1 Viewer)

[rsingh]

Hey guys,

These two topics are my worst and I've found that not many people favour them. But anyway, I was wondering, given a probability question in 3u, how can you determine whether to use Perms/Combs to answer it, or binomial probability? Like how can you tell whether its a question requiring one or the other?

Any help would be greaT!
Thanks.

 

[acmilan]

If there are only two possible outcomes, then it will be binomial. Eg. if they ask the probability of getting a heads or tails, it will be binomial since there are only 2 possible outcomes.

If there are many possible outcomes then it will either be permutations or combinations, depending on whether order matters. Eg. if its a question about a deck of cards, the it will most likely be permutations since there are 52 cards in a deck

 

[tennille]

Also, if the question relates to choosing people for a commitee, it's most likely to be combinations because order doesn't really matter. Although I remember having a question like that in my trial exam and it turned out to be permutations because order mattered in some way (can't really remember the question).

 

[FinalFantasy]

just do it logically and u dun even need to know what topic it is....

 

[who_loves_maths]

rsingh, like what acmilan has said, if the "trials" have two possible outcomes only, then it's most probably a binomial question. however, you also need to know that in case you really can't differetiate a question in terms of using either perms/combs or binomial, then just apply the Perms/Combs method(s)... since the theory of binomial probability is itself simply a manifestation of perms/combs.