Question

An unbiased coin is tossed four times. Find the probability of the given event. (Round your answer to four decimal places.)
The coin lands heads more than once.

Answer 1

The probability of the coin landing on head with each toss is 1/2. The probability of two or more independent events all happening is the probability of the individual events, multiplied.

So where X = the number of heads in four coin tosses:

P(X = 2) = 0.5 ^ 2 = 0.25
P(X = 3) = 0.5 ^3 = 0.125
P(X = 4) = 0.5 ^4 = 0.0625

So the probability of all those things happening is P(X = 2) + P(X = 3) + P(X = 4).
0.25 + 0.125 + 0.0625 = 0.4375.

I'm a biologist so check my computation.