# What is the variance of 10 coin flips?

##### 1 Answer

Nov 2, 2015

Assuming that the coins are unbiased, the answer is 2.5.

#### Explanation:

Flipping coins comes under the binomial distribution. For a binomial distribution, the parameters are n, p, and q. The variance is then given by npq.

Here, 10 coins are flipped. so n = 10

the coin is unbiased - so p =#(1/2)#

q = 1 - p = 1 -#(1/2)# =#(1/2)#

variance is 10#(1/2)# #(1/2)# = 2.5