Question 547741: An experiment consists of flipping two coins and noting the face of each coin as
Heads or Tails.
a)What is the sample space for this experiment?
b. What is the probability of getting exactly two heads?
c. What is the probability of getting at least one head.
Answer by mathie123(224)   (Show Source):
You can put this solution on YOUR website! a) the sample space is all the possible outcomes.
If H is heads and T is tails, we can can get these outcomes:
{{H,H},{H,T},{T,T}, {T, H}}
That's the sample space !
b) Looking at our sample space, there is one outcome with H,H (2 heads) and a total of 4 possibilities. So this probability is 
c) This is similar to the last. The trick being AT LEAST ONE HEAD means we could have one head, or two heads.....
Looking at the sample space there is 3 options where this is possible, again a total of 4 possibilities
So the probability of at least one heads is  .
Note: once you get into larger sample spaces an easier way to do it is take the total  and subtract the probability of getting no heads .  (It's not a coincidence that the two answers are the same..)
Hopefully this helps.
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