# Math Help - Calculate the probability

1. ## Calculate the probability

Calculate the probability of tossing exactly 2 heads in 5 coin tosses

2. Originally Posted by shelleeblue
Calculate the probability of tossing exactly 2 heads in 5 coin tosses
Binomial probability problem. Probability of success (a head) on a single toss
is p=0.5. The probability of exactly n success in N trials is:

P(n,N)=N!/[n! (N-n)!] p^n (1-p)^(N-n)

so in this case:

P(2,5)=5!/[2! 3!] 0.5^5 = 0.3125

RonL