If a coin is tossed 2,000,000 times, what is the probability that it will come up exactly 1,000,000 times each heads and tails?
By the problem, X~ Binomial (n, p), where:
n=2,000, 0000 and p=0.5
= comb(2000000, 1000000)/(2^2000000)
Consequently, the required probability is approximately 0.00056