Question

Calculate the probability of landing exactly 3 heads when a fair coin is tossed 5 times.

Answer 1

0.3125

Explanation:

When a fair coin is tossed we find that

there are only two outcomes

Each toss is independent of the other

Hence if Xis no of heads then X is binomial with n = 5 and p = 0.5

Using binomial formula we can find probability for getting 3 heads exactly.

Required probability

= P(X=3)

=
`5C3(0.5)^3 (0.5)^2\\= 10(0.5)^5\\=0.3125`