You have to read this article before this to make sense of what I'm saying here. After putting up the probability distribution and showing that after playing 100 toss of coin, where each head gives you $2 and each tail takes away $1 from you, will not always give you a positive returns, I was still unsatisfied. I went ahead and did a monte carlo simulation of the game on excel. Using RAND() function, I will get a random value between 0 and 1. I programmed it such that if I have a number bigger or equal to 0.5, it'll be heads and I'll assign a value of 1 to it. If not, it'll be tails and I'll assign a value of 0 to it. IF( cell >= 0.5, 1, 0)  After tallying the number of heads and tails, I proceed to count the gain/loss from this 100 ......