A fair coin is flipped four times. What is the probability of getting heads at least once? Write your answer as a simplified fraction.

Question

anonymous · Answer

pls use the complement approach

anonymous · Answer

That's what I would have thought anyway.  What's the probability of not getting heads at all?

anonymous · Answer

ah the probability is getting all tails

anonymous · Answer

Which is?

anonymous · Answer

it is 1/2*1/2*1/2*1/2

anonymous · Answer

1/16

anonymous · Answer

so whts ur reply?

anonymous · Answer

Yes, that's correct.  Now, there are only two possibilities:  Either we get no heads or at all, or we get at least one.  So, since the probabilities must add to one, what do we get?

anonymous · Answer

p(of having atlesat one head)=1-p(of having no head)

anonymous · Answer

1-1/16=15/16

anonymous · Answer

there ya go

anonymous · Answer

welll my maths sucks

anonymous · Answer

Hahah well you handled that fine

anonymous · Answer

is there any algorith to solve probability ques

anonymous · Answer

No, they need to be solved on a case-by-case basis.

directrix · Answer

You can use Binomial Probability Distributions to solve the problem. It is an algorithm of sorts. P(at least 1 H) = 1 - P(0H) = 1 - C(4,0) (1/2)^0 (1/2)^4 = 1 - 1 (1/16) = 15/16. Note that C(4,0) is combinatorial notation for 4 choose 0. Check out this video on binomial probabilities: http://www.youtube.com/watch?v=xNLQuuvE9ug

anonymous · Answer

what is a combinatoral notation?

directrix · Answer

http://mathworld.wolfram.com/Combination.html Also, http://mathworld.wolfram.com/Combinatorics.html

anonymous · Answer

got it u are taking about combination notation of nCr.....

anonymous · Answer

murray what is the other notations for combinations

directrix · Answer

|dw:1327912574413:dw|