Obtain the variance of a bernoulli random variable X with the probabikity of success P = 0.5

Answer 1

The expected value of a bernoulli random variable is the probability of success, p. So E[X] = .5

The variance of a bernoulli random variable is the probability of success times the probability of failure. Since the probability of failure equals the probability of success in this case, the variance is Var[X] = .5 x .5 = .25