I am relatively sure there is an easy answer to this, but, after searching, I don't know what it is. within excel I want to simulate wins and losses separately based on the avg and std dev of both. for example: avg win: $300 std dev of wins: $200 avg loss: $200 std dev of losses: $150 first I determine if a trade is a win or loss then simulate the amount. my problem is that, using a normal distribution, I can come up with negative win amounts and positive loss amounts at times. I realize I probably shouldn't use a normal dist (leaving aside fat tails, etc) as the results don't truncate at $0 but I don't know what else to use. Should I use some other type of distribution or is there a mathematical/statistical technique that can be used to truncate a normal distr at 0? Hopefully this is clear and thanks in advance.