Question

QUESTION 9 4 Problem 9) A fair coin is tossed 20 times. A fair coin means that the probability of getting a head is the same as the probability of getting a tail. Let X be the number of coins of getting head. Note that there are only two possible outcomes: getting head or tail after tossing the coin X follows a binomial distribution with n -20.p=0.5. Answer the following questions. (Question) Find the variance of X, Var(X).

Answer 1

Given,

n = 20

p = 0.5

For the binomial distribution,

Var (x) = n*p*(1-p)

Var (x) = 20 * 0.5 * ( 1 - 0.5 )

Var(x) = 5.