SOLUTION: Four fair coins are flipped. What is the probability of getting three or more heads?

Algebra ->  Algebra  -> Probability-and-statistics -> SOLUTION: Four fair coins are flipped. What is the probability of getting three or more heads?      Log On

Ad: Algebra Solved!™: algebra software solves algebra homework problems with step-by-step help!
Ad: Algebrator™ solves your algebra problems and provides step-by-step explanations!

   

Question 610796: Four fair coins are flipped. What is the probability of getting three or more heads?
Answer by richard1234(5390) About Me  (Show Source):
You can put this solution on YOUR website!
We could use a binomcdf but this is very easy to do by hand.

P(4 heads) is simply (1/2)^4 = 1/16.

P(3 heads) is (4C3)(1/2)^4 = 1/4.

Therefore P(3 or more heads) is equal to 1/4 + 1/16, or 5/16.